<?xml version="1.0" encoding="US-ASCII"?>
<!--XBRL Document Created with Wdesk from Workiva-->
<!-- -->
<linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <roleRef roleURI="http://www.westlake.com/role/AccountsReceivableThirdParties" xlink:href="wlkp-20160930.xsd#AccountsReceivableThirdParties" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/AccountsReceivableThirdPartiesAccountsReceivablethirdPartiesScheduleOfAccountsReceivableDetails" xlink:href="wlkp-20160930.xsd#AccountsReceivableThirdPartiesAccountsReceivablethirdPartiesScheduleOfAccountsReceivableDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/AccountsReceivableThirdPartiesTables" xlink:href="wlkp-20160930.xsd#AccountsReceivableThirdPartiesTables" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/AccumulatedOtherComprehensiveLossIncome" xlink:href="wlkp-20160930.xsd#AccumulatedOtherComprehensiveLossIncome" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/AccumulatedOtherComprehensiveLossIncomeDetails" xlink:href="wlkp-20160930.xsd#AccumulatedOtherComprehensiveLossIncomeDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/AccumulatedOtherComprehensiveLossIncomeTables" xlink:href="wlkp-20160930.xsd#AccumulatedOtherComprehensiveLossIncomeTables" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/CommitmentsAndContingencies" xlink:href="wlkp-20160930.xsd#CommitmentsAndContingencies" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/CommitmentsAndContingenciesDetails" xlink:href="wlkp-20160930.xsd#CommitmentsAndContingenciesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/ConsolidatedBalanceSheets" xlink:href="wlkp-20160930.xsd#ConsolidatedBalanceSheets" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:href="wlkp-20160930.xsd#ConsolidatedBalanceSheetsParenthetical" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/ConsolidatedStatementsOfCashFlows" xlink:href="wlkp-20160930.xsd#ConsolidatedStatementsOfCashFlows" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/ConsolidatedStatementsOfChangesInEquity" xlink:href="wlkp-20160930.xsd#ConsolidatedStatementsOfChangesInEquity" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/ConsolidatedStatementsOfComprehensiveIncome" xlink:href="wlkp-20160930.xsd#ConsolidatedStatementsOfComprehensiveIncome" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/ConsolidatedStatementsOfOperations" xlink:href="wlkp-20160930.xsd#ConsolidatedStatementsOfOperations" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/DerivativeInstruments" xlink:href="wlkp-20160930.xsd#DerivativeInstruments" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/DerivativeInstrumentsDetails" xlink:href="wlkp-20160930.xsd#DerivativeInstrumentsDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/DerivativeInstrumentsIneffectivePortionDetails" xlink:href="wlkp-20160930.xsd#DerivativeInstrumentsIneffectivePortionDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/DerivativeInstrumentsTables" xlink:href="wlkp-20160930.xsd#DerivativeInstrumentsTables" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/DescriptionOfBusinessAndBasisOfPresentation" xlink:href="wlkp-20160930.xsd#DescriptionOfBusinessAndBasisOfPresentation" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/DescriptionOfBusinessAndBasisOfPresentationDetails" xlink:href="wlkp-20160930.xsd#DescriptionOfBusinessAndBasisOfPresentationDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/DescriptionOfBusinessAndBasisOfPresentationPolicies" xlink:href="wlkp-20160930.xsd#DescriptionOfBusinessAndBasisOfPresentationPolicies" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/DistributionsAndNetIncomePerLimitedPartnerUnit" xlink:href="wlkp-20160930.xsd#DistributionsAndNetIncomePerLimitedPartnerUnit" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/DistributionsAndNetIncomePerLimitedPartnerUnitBasicAndDilutedIncomePerLimitedPartnerUnitDetails" xlink:href="wlkp-20160930.xsd#DistributionsAndNetIncomePerLimitedPartnerUnitBasicAndDilutedIncomePerLimitedPartnerUnitDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/DistributionsAndNetIncomePerLimitedPartnerUnitDistributionsDeclaredDetails" xlink:href="wlkp-20160930.xsd#DistributionsAndNetIncomePerLimitedPartnerUnitDistributionsDeclaredDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/DistributionsAndNetIncomePerLimitedPartnerUnitIncomeInExcessOfDistributionDetails" xlink:href="wlkp-20160930.xsd#DistributionsAndNetIncomePerLimitedPartnerUnitIncomeInExcessOfDistributionDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/DistributionsAndNetIncomePerLimitedPartnerUnitTables" xlink:href="wlkp-20160930.xsd#DistributionsAndNetIncomePerLimitedPartnerUnitTables" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/DocumentAndEntityInformation" xlink:href="wlkp-20160930.xsd#DocumentAndEntityInformation" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/FairValueMeasurements" xlink:href="wlkp-20160930.xsd#FairValueMeasurements" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/FairValueMeasurementsSummaryOfAssetsAndLiabilitiesAccountedAtFairValueOnRecurringAndNonrecurringBasisDetails" xlink:href="wlkp-20160930.xsd#FairValueMeasurementsSummaryOfAssetsAndLiabilitiesAccountedAtFairValueOnRecurringAndNonrecurringBasisDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/FairValueMeasurementsSummaryOfCarryingAndFairValuesOfLongTermDebtDetails" xlink:href="wlkp-20160930.xsd#FairValueMeasurementsSummaryOfCarryingAndFairValuesOfLongTermDebtDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/FairValueMeasurementsTables" xlink:href="wlkp-20160930.xsd#FairValueMeasurementsTables" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/FinancialInstruments" xlink:href="wlkp-20160930.xsd#FinancialInstruments" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/FinancialInstrumentsDetails" xlink:href="wlkp-20160930.xsd#FinancialInstrumentsDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/Inventories" xlink:href="wlkp-20160930.xsd#Inventories" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/InventoriesDetails" xlink:href="wlkp-20160930.xsd#InventoriesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/InventoriesTables" xlink:href="wlkp-20160930.xsd#InventoriesTables" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/LongTermDebtPayableToWestlake" xlink:href="wlkp-20160930.xsd#LongTermDebtPayableToWestlake" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/LongTermDebtPayableToWestlakeDetails" xlink:href="wlkp-20160930.xsd#LongTermDebtPayableToWestlakeDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/LongTermDebtPayableToWestlakeTables" xlink:href="wlkp-20160930.xsd#LongTermDebtPayableToWestlakeTables" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/MajorCustomerAndConcentrationRisk" xlink:href="wlkp-20160930.xsd#MajorCustomerAndConcentrationRisk" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/MajorCustomerAndConcentrationRiskDetails" xlink:href="wlkp-20160930.xsd#MajorCustomerAndConcentrationRiskDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/OtherAssets" xlink:href="wlkp-20160930.xsd#OtherAssets" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/OtherAssetsDetails" xlink:href="wlkp-20160930.xsd#OtherAssetsDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/OtherAssetsTables" xlink:href="wlkp-20160930.xsd#OtherAssetsTables" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/PropertyPlantAndEquipment" xlink:href="wlkp-20160930.xsd#PropertyPlantAndEquipment" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/PropertyPlantAndEquipmentDetail" xlink:href="wlkp-20160930.xsd#PropertyPlantAndEquipmentDetail" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactions" xlink:href="wlkp-20160930.xsd#RelatedPartyTransactions" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsAccountsReceivableFromAndAccountsPayableToRelatedPartiesDetails" xlink:href="wlkp-20160930.xsd#RelatedPartyTransactionsAccountsReceivableFromAndAccountsPayableToRelatedPartiesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsCostOfSalesFromRelatedPartiesDetails" xlink:href="wlkp-20160930.xsd#RelatedPartyTransactionsCostOfSalesFromRelatedPartiesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsDebtPayableToRelatedPartiesDetails" xlink:href="wlkp-20160930.xsd#RelatedPartyTransactionsDebtPayableToRelatedPartiesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsGeneralDetails" xlink:href="wlkp-20160930.xsd#RelatedPartyTransactionsGeneralDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsGoodsAndServicesFromRelatedPartiesThatHaveBeenCapitalizedDetails" xlink:href="wlkp-20160930.xsd#RelatedPartyTransactionsGoodsAndServicesFromRelatedPartiesThatHaveBeenCapitalizedDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsSalesToRelatedPartiesDetails" xlink:href="wlkp-20160930.xsd#RelatedPartyTransactionsSalesToRelatedPartiesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsServicesFromRelatedPartiesIncludedInSgaExpensesDetails" xlink:href="wlkp-20160930.xsd#RelatedPartyTransactionsServicesFromRelatedPartiesIncludedInSgaExpensesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsSiteLeaseAgreementsDetails" xlink:href="wlkp-20160930.xsd#RelatedPartyTransactionsSiteLeaseAgreementsDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsTables" xlink:href="wlkp-20160930.xsd#RelatedPartyTransactionsTables" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/SubsequentEvents" xlink:href="wlkp-20160930.xsd#SubsequentEvents" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/SubsequentEventsDetails" xlink:href="wlkp-20160930.xsd#SubsequentEventsDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/SupplementalInformation" xlink:href="wlkp-20160930.xsd#SupplementalInformation" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/SupplementalInformationDetails" xlink:href="wlkp-20160930.xsd#SupplementalInformationDetails" xlink:type="simple" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" xlink:type="simple" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" xlink:type="simple" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" xlink:type="simple" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" xlink:type="simple" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" xlink:type="simple" />
  <definitionLink xlink:role="http://www.westlake.com/role/AccountsReceivableThirdParties" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/AccountsReceivableThirdPartiesAccountsReceivablethirdPartiesScheduleOfAccountsReceivableDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/AccountsReceivableThirdPartiesTables" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/AccumulatedOtherComprehensiveLossIncome" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/AccumulatedOtherComprehensiveLossIncomeDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_0923384983AB8A359A3E0AD5ECA65571" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_C83B15A686B9C4B56BA50AD5ECA4F059" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_0923384983AB8A359A3E0AD5ECA65571" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_C83B15A686B9C4B56BA50AD5ECA4F059" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_6A8FB86E2C946C9644EC0AD5ECA57796" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_C83B15A686B9C4B56BA50AD5ECA4F059" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_6A8FB86E2C946C9644EC0AD5ECA57796" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_3D687F6B5E4C4BCF2A910AD5ECA566B4_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_6A8FB86E2C946C9644EC0AD5ECA57796" xlink:to="loc_us-gaap_EquityComponentDomain_3D687F6B5E4C4BCF2A910AD5ECA566B4_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_3D687F6B5E4C4BCF2A910AD5ECA566B4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_6A8FB86E2C946C9644EC0AD5ECA57796" xlink:to="loc_us-gaap_EquityComponentDomain_3D687F6B5E4C4BCF2A910AD5ECA566B4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember" xlink:label="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_835BE3E777082895A4E10AD5ECA5DF16" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_3D687F6B5E4C4BCF2A910AD5ECA566B4" xlink:to="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_835BE3E777082895A4E10AD5ECA5DF16" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_BFD5DF48E6B8626144260AD5ECA6583B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_0923384983AB8A359A3E0AD5ECA65571" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_BFD5DF48E6B8626144260AD5ECA6583B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_4BE3F8DAD2061ECA2B510AD5ECA6535F" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_0923384983AB8A359A3E0AD5ECA65571" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_4BE3F8DAD2061ECA2B510AD5ECA6535F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_3F7A78DB620FDC2E51410AD5ECA64935" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_0923384983AB8A359A3E0AD5ECA65571" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_3F7A78DB620FDC2E51410AD5ECA64935" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/AccumulatedOtherComprehensiveLossIncomeTables" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/CommitmentsAndContingencies" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/CommitmentsAndContingenciesDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LossContingenciesLineItems" xlink:label="loc_us-gaap_LossContingenciesLineItems_63704B54924A5720CB7B1BE28DA40ADA" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LossContingenciesTable" xlink:label="loc_us-gaap_LossContingenciesTable_AB97A64AC2DE12AA7E741BE28DA49CC2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_63704B54924A5720CB7B1BE28DA40ADA" xlink:to="loc_us-gaap_LossContingenciesTable_AB97A64AC2DE12AA7E741BE28DA49CC2" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LitigationStatusAxis" xlink:label="loc_us-gaap_LitigationStatusAxis_F43E74E94604C82A5C4D1BE28DA46B10" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_AB97A64AC2DE12AA7E741BE28DA49CC2" xlink:to="loc_us-gaap_LitigationStatusAxis_F43E74E94604C82A5C4D1BE28DA46B10" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LitigationStatusDomain" xlink:label="loc_us-gaap_LitigationStatusDomain_0E2754BB837F6D30DEB71BE28DA41E5E_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LitigationStatusAxis_F43E74E94604C82A5C4D1BE28DA46B10" xlink:to="loc_us-gaap_LitigationStatusDomain_0E2754BB837F6D30DEB71BE28DA41E5E_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LitigationStatusDomain" xlink:label="loc_us-gaap_LitigationStatusDomain_0E2754BB837F6D30DEB71BE28DA41E5E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LitigationStatusAxis_F43E74E94604C82A5C4D1BE28DA46B10" xlink:to="loc_us-gaap_LitigationStatusDomain_0E2754BB837F6D30DEB71BE28DA41E5E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PendingLitigationMember" xlink:label="loc_us-gaap_PendingLitigationMember_8101623D224D69EE62411BE28DA46B9C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LitigationStatusDomain_0E2754BB837F6D30DEB71BE28DA41E5E" xlink:to="loc_us-gaap_PendingLitigationMember_8101623D224D69EE62411BE28DA46B9C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SettledLitigationMember" xlink:label="loc_us-gaap_SettledLitigationMember_3BA24D5172AAAC2D3B401BE28DA48539" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LitigationStatusDomain_0E2754BB837F6D30DEB71BE28DA41E5E" xlink:to="loc_us-gaap_SettledLitigationMember_3BA24D5172AAAC2D3B401BE28DA48539" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LossContingenciesByNatureOfContingencyAxis" xlink:label="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_A6FB960E9B47E0BA96FD1BE28DA478FF" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_AB97A64AC2DE12AA7E741BE28DA49CC2" xlink:to="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_A6FB960E9B47E0BA96FD1BE28DA478FF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LossContingencyNatureDomain" xlink:label="loc_us-gaap_LossContingencyNatureDomain_7FC8201A7B891F7DE8F61BE28DA427C9_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_A6FB960E9B47E0BA96FD1BE28DA478FF" xlink:to="loc_us-gaap_LossContingencyNatureDomain_7FC8201A7B891F7DE8F61BE28DA427C9_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LossContingencyNatureDomain" xlink:label="loc_us-gaap_LossContingencyNatureDomain_7FC8201A7B891F7DE8F61BE28DA427C9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_A6FB960E9B47E0BA96FD1BE28DA478FF" xlink:to="loc_us-gaap_LossContingencyNatureDomain_7FC8201A7B891F7DE8F61BE28DA427C9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UnfavorableRegulatoryActionMember" xlink:label="loc_us-gaap_UnfavorableRegulatoryActionMember_C15214C3DBF2CAD8EF561BE28DA4A58E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingencyNatureDomain_7FC8201A7B891F7DE8F61BE28DA427C9" xlink:to="loc_us-gaap_UnfavorableRegulatoryActionMember_C15214C3DBF2CAD8EF561BE28DA4A58E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LossContingencyEstimateOfPossibleLoss" xlink:label="loc_us-gaap_LossContingencyEstimateOfPossibleLoss_ADBA05CC3F280B5249131BE28DA4B002" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_63704B54924A5720CB7B1BE28DA40ADA" xlink:to="loc_us-gaap_LossContingencyEstimateOfPossibleLoss_ADBA05CC3F280B5249131BE28DA4B002" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LossContingencyClaimsSettledNumber" xlink:label="loc_us-gaap_LossContingencyClaimsSettledNumber_9901CA697E77EB6EAF591BE28DA4180D" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_63704B54924A5720CB7B1BE28DA40ADA" xlink:to="loc_us-gaap_LossContingencyClaimsSettledNumber_9901CA697E77EB6EAF591BE28DA4180D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LitigationSettlementAmount" xlink:label="loc_us-gaap_LitigationSettlementAmount_571108906AB8A775BE701BE28DA4437C" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_63704B54924A5720CB7B1BE28DA40ADA" xlink:to="loc_us-gaap_LitigationSettlementAmount_571108906AB8A775BE701BE28DA4437C" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/ConsolidatedBalanceSheets" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_EED957FA31EC706EF6061BE28FA23173" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_0169C0E3F0EF2DB126091BE28FA2BF97" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_EED957FA31EC706EF6061BE28FA23173" xlink:to="loc_us-gaap_StatementTable_0169C0E3F0EF2DB126091BE28FA2BF97" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_2058C62A0196E238AFF01BE28FA2F449" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_0169C0E3F0EF2DB126091BE28FA2BF97" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_2058C62A0196E238AFF01BE28FA2F449" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_EF4BC74E1F820A46D5E11BE28FA24FF3_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_2058C62A0196E238AFF01BE28FA2F449" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_EF4BC74E1F820A46D5E11BE28FA24FF3_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_EF4BC74E1F820A46D5E11BE28FA24FF3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_2058C62A0196E238AFF01BE28FA2F449" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_EF4BC74E1F820A46D5E11BE28FA24FF3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnerMember" xlink:label="loc_us-gaap_LimitedPartnerMember_46B3FA8AFC6DA7C556491BE28FA21D88" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_EF4BC74E1F820A46D5E11BE28FA24FF3" xlink:to="loc_us-gaap_LimitedPartnerMember_46B3FA8AFC6DA7C556491BE28FA21D88" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_GeneralPartnerMember" xlink:label="loc_us-gaap_GeneralPartnerMember_2A778C22235C353708DA1BE28FA2A106" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_EF4BC74E1F820A46D5E11BE28FA24FF3" xlink:to="loc_us-gaap_GeneralPartnerMember_2A778C22235C353708DA1BE28FA2A106" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_35E2D96FA223D498D2441BE28FA25E31" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_0169C0E3F0EF2DB126091BE28FA2BF97" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_35E2D96FA223D498D2441BE28FA25E31" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_29CA5D4ABB170C190BBC1BE28FA2CF02_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_35E2D96FA223D498D2441BE28FA25E31" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_29CA5D4ABB170C190BBC1BE28FA2CF02_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_29CA5D4ABB170C190BBC1BE28FA2CF02" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_35E2D96FA223D498D2441BE28FA25E31" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_29CA5D4ABB170C190BBC1BE28FA2CF02" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_CommonUnitsMember" xlink:label="loc_wlkp_CommonUnitsMember_C75625099694F8DF73CA1BE28FA2EAF3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_29CA5D4ABB170C190BBC1BE28FA2CF02" xlink:to="loc_wlkp_CommonUnitsMember_C75625099694F8DF73CA1BE28FA2EAF3" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_SubordinatedUnitsMember" xlink:label="loc_wlkp_SubordinatedUnitsMember_9843B96510EEF2D998D31BE28FA2FB33" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_29CA5D4ABB170C190BBC1BE28FA2CF02" xlink:to="loc_wlkp_SubordinatedUnitsMember_9843B96510EEF2D998D31BE28FA2FB33" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_AEE3AA12D693BF1200761BE28FA2B5C5" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_0169C0E3F0EF2DB126091BE28FA2BF97" xlink:to="loc_us-gaap_CounterpartyNameAxis_AEE3AA12D693BF1200761BE28FA2B5C5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_90BAA83092F521058B021BE28FA207A5_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_AEE3AA12D693BF1200761BE28FA2B5C5" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_90BAA83092F521058B021BE28FA207A5_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_90BAA83092F521058B021BE28FA207A5" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_AEE3AA12D693BF1200761BE28FA2B5C5" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_90BAA83092F521058B021BE28FA207A5" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_UnidentifiedThirdPartiesMember" xlink:label="loc_wlkp_UnidentifiedThirdPartiesMember_F86CCA933820647DCB3E1BE28FA23E71" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_90BAA83092F521058B021BE28FA207A5" xlink:to="loc_wlkp_UnidentifiedThirdPartiesMember_F86CCA933820647DCB3E1BE28FA23E71" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_B20715290451770413231BE28FA2157D" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_90BAA83092F521058B021BE28FA207A5" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_B20715290451770413231BE28FA2157D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaap_AssetsAbstract_5B5D8392B3B8A91FAC011BE28FA2FE40" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_EED957FA31EC706EF6061BE28FA23173" xlink:to="loc_us-gaap_AssetsAbstract_5B5D8392B3B8A91FAC011BE28FA2FE40" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="loc_us-gaap_AssetsCurrentAbstract_8B2F1FB2C514B6BAD1101BE28FA2169E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_5B5D8392B3B8A91FAC011BE28FA2FE40" xlink:to="loc_us-gaap_AssetsCurrentAbstract_8B2F1FB2C514B6BAD1101BE28FA2169E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_A74FD4566483337EE0411BE28FA2C2CE" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_8B2F1FB2C514B6BAD1101BE28FA2169E" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_A74FD4566483337EE0411BE28FA2C2CE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccountsReceivableRelatedPartiesCurrent" xlink:label="loc_us-gaap_AccountsReceivableRelatedPartiesCurrent_BE9374129F55544BEF711BE28FA21131" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_8B2F1FB2C514B6BAD1101BE28FA2169E" xlink:to="loc_us-gaap_AccountsReceivableRelatedPartiesCurrent_BE9374129F55544BEF711BE28FA21131" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ReceivablesNetCurrent" xlink:label="loc_us-gaap_ReceivablesNetCurrent_EBBB294EDA1A1721434E1BE28FA2C61B" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_8B2F1FB2C514B6BAD1101BE28FA2169E" xlink:to="loc_us-gaap_ReceivablesNetCurrent_EBBB294EDA1A1721434E1BE28FA2C61B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_6917AB19397E55F967D61BE28FA2ED60" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_8B2F1FB2C514B6BAD1101BE28FA2169E" xlink:to="loc_us-gaap_InventoryNet_6917AB19397E55F967D61BE28FA2ED60" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_FCF0143963D5F3A6C3131BE28FA2FB74" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_8B2F1FB2C514B6BAD1101BE28FA2169E" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_FCF0143963D5F3A6C3131BE28FA2FB74" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent_F1E33497149194ABB1CA1BE28FA2188C" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_8B2F1FB2C514B6BAD1101BE28FA2169E" xlink:to="loc_us-gaap_AssetsCurrent_F1E33497149194ABB1CA1BE28FA2188C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_0BDF713B71E92435F8AF1BE28FA2A6A3" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_5B5D8392B3B8A91FAC011BE28FA2FE40" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_0BDF713B71E92435F8AF1BE28FA2A6A3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccountsReceivableRelatedPartiesNoncurrent" xlink:label="loc_us-gaap_AccountsReceivableRelatedPartiesNoncurrent_AFD9D7E22E131760F2A11BE28FA2D56F" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_5B5D8392B3B8A91FAC011BE28FA2FE40" xlink:to="loc_us-gaap_AccountsReceivableRelatedPartiesNoncurrent_AFD9D7E22E131760F2A11BE28FA2D56F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherAssetsAbstract" xlink:label="loc_us-gaap_OtherAssetsAbstract_63398421F955A9A15E701BE28FA21BDA" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_5B5D8392B3B8A91FAC011BE28FA2FE40" xlink:to="loc_us-gaap_OtherAssetsAbstract_63398421F955A9A15E701BE28FA21BDA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill_8E8B714C5EAEE3AAA47E1BE28FA2283D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherAssetsAbstract_63398421F955A9A15E701BE28FA21BDA" xlink:to="loc_us-gaap_Goodwill_8E8B714C5EAEE3AAA47E1BE28FA2283D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredCostsAndOtherAssets" xlink:label="loc_us-gaap_DeferredCostsAndOtherAssets_04968B30ECD09B9AAEFA1BE28FA2D17A" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherAssetsAbstract_63398421F955A9A15E701BE28FA21BDA" xlink:to="loc_us-gaap_DeferredCostsAndOtherAssets_04968B30ECD09B9AAEFA1BE28FA2D17A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_DF9FC8CAB8BF25C58A8C1BE28FA216D2" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherAssetsAbstract_63398421F955A9A15E701BE28FA21BDA" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_DF9FC8CAB8BF25C58A8C1BE28FA216D2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_61DDB8A6D1A8DDEDB4ED1BE28FA2BB2C" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_5B5D8392B3B8A91FAC011BE28FA2FE40" xlink:to="loc_us-gaap_Assets_61DDB8A6D1A8DDEDB4ED1BE28FA2BB2C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_3213E4ECEBEC73E4762A1BE28FA234AA" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_EED957FA31EC706EF6061BE28FA23173" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_3213E4ECEBEC73E4762A1BE28FA234AA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_C3FDFFAD88217CE8A17F1BE28FA22201" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_3213E4ECEBEC73E4762A1BE28FA234AA" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_C3FDFFAD88217CE8A17F1BE28FA22201" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccountsPayableRelatedPartiesCurrent" xlink:label="loc_us-gaap_AccountsPayableRelatedPartiesCurrent_6974198F5238854EF7521BE28FA2C23B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_C3FDFFAD88217CE8A17F1BE28FA22201" xlink:to="loc_us-gaap_AccountsPayableRelatedPartiesCurrent_6974198F5238854EF7521BE28FA2C23B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="loc_us-gaap_AccountsPayableCurrent_44FA4E53AC8ACC905F361BE28FA217B1" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_C3FDFFAD88217CE8A17F1BE28FA22201" xlink:to="loc_us-gaap_AccountsPayableCurrent_44FA4E53AC8ACC905F361BE28FA217B1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_BA9690FDDBAEC7B3AA0C1BE28FA2AF1D" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_C3FDFFAD88217CE8A17F1BE28FA22201" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_BA9690FDDBAEC7B3AA0C1BE28FA2AF1D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaap_LiabilitiesCurrent_CEF31B45E5296FBAFF5B1BE28FA2631E" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_C3FDFFAD88217CE8A17F1BE28FA22201" xlink:to="loc_us-gaap_LiabilitiesCurrent_CEF31B45E5296FBAFF5B1BE28FA2631E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DueToRelatedPartiesNoncurrent" xlink:label="loc_us-gaap_DueToRelatedPartiesNoncurrent_6B2F694B7A5BC22F88261BE28FA2FA12" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_3213E4ECEBEC73E4762A1BE28FA234AA" xlink:to="loc_us-gaap_DueToRelatedPartiesNoncurrent_6B2F694B7A5BC22F88261BE28FA2FA12" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxLiabilitiesNoncurrent" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesNoncurrent_238B9E1EA68235A4D1D91BE28FA26D25" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_3213E4ECEBEC73E4762A1BE28FA234AA" xlink:to="loc_us-gaap_DeferredTaxLiabilitiesNoncurrent_238B9E1EA68235A4D1D91BE28FA26D25" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_437952F17BFD1E23959B1BE28FA20A19" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_3213E4ECEBEC73E4762A1BE28FA234AA" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_437952F17BFD1E23959B1BE28FA20A19" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities_3A7230FFA406F01B697A1BE28FA22031" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_3213E4ECEBEC73E4762A1BE28FA234AA" xlink:to="loc_us-gaap_Liabilities_3A7230FFA406F01B697A1BE28FA22031" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="loc_us-gaap_CommitmentsAndContingencies_C05DEBF99D892EBC01011BE28FA2D6E1" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_3213E4ECEBEC73E4762A1BE28FA234AA" xlink:to="loc_us-gaap_CommitmentsAndContingencies_C05DEBF99D892EBC01011BE28FA2D6E1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StockholdersEquityAbstract" xlink:label="loc_us-gaap_StockholdersEquityAbstract_766A8B9C0B903DB1AB851BE28FA29E1F" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_EED957FA31EC706EF6061BE28FA23173" xlink:to="loc_us-gaap_StockholdersEquityAbstract_766A8B9C0B903DB1AB851BE28FA29E1F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccount" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccount_87769ACCF0B9BEDA2F021BE28FA2F981" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_766A8B9C0B903DB1AB851BE28FA29E1F" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccount_87769ACCF0B9BEDA2F021BE28FA2F981" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_GeneralPartnersCapitalAccount" xlink:label="loc_us-gaap_GeneralPartnersCapitalAccount_DE1C1723E2B312182C0C1BE28FA2202E" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_766A8B9C0B903DB1AB851BE28FA29E1F" xlink:to="loc_us-gaap_GeneralPartnersCapitalAccount_DE1C1723E2B312182C0C1BE28FA2202E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_C8226563871B33D665151BE28FA2217D" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_766A8B9C0B903DB1AB851BE28FA29E1F" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_C8226563871B33D665151BE28FA2217D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PartnersCapital" xlink:label="loc_us-gaap_PartnersCapital_17BAC52B52F3C48450C11BE28FA2D0C7" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_766A8B9C0B903DB1AB851BE28FA29E1F" xlink:to="loc_us-gaap_PartnersCapital_17BAC52B52F3C48450C11BE28FA2D0C7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MinorityInterestInLimitedPartnerships" xlink:label="loc_us-gaap_MinorityInterestInLimitedPartnerships_A06A824AEA3DF16FF6671BE28FA21D12" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_766A8B9C0B903DB1AB851BE28FA29E1F" xlink:to="loc_us-gaap_MinorityInterestInLimitedPartnerships_A06A824AEA3DF16FF6671BE28FA21D12" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_AF060607980A81F1F2DF1BE28FA2A591" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_766A8B9C0B903DB1AB851BE28FA29E1F" xlink:to="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_AF060607980A81F1F2DF1BE28FA2A591" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_C89E0FE474DAD8FEA9D81BE28FA2978B" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_766A8B9C0B903DB1AB851BE28FA29E1F" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_C89E0FE474DAD8FEA9D81BE28FA2978B" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_7301E855EF7D793D4E3676207BE76446" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_3E7415899A92287F152C76207BE6BA8F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_7301E855EF7D793D4E3676207BE76446" xlink:to="loc_us-gaap_StatementTable_3E7415899A92287F152C76207BE6BA8F" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_0CB550F22F4EC2A3D46A76207BE6C58F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_3E7415899A92287F152C76207BE6BA8F" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_0CB550F22F4EC2A3D46A76207BE6C58F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_924EC04506A3BAAB15F376207BE6F771_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_0CB550F22F4EC2A3D46A76207BE6C58F" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_924EC04506A3BAAB15F376207BE6F771_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_924EC04506A3BAAB15F376207BE6F771" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_0CB550F22F4EC2A3D46A76207BE6C58F" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_924EC04506A3BAAB15F376207BE6F771" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_CommonUnitsMember" xlink:label="loc_wlkp_CommonUnitsMember_01CE8C8DC2702F3A244976207BE755C2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_924EC04506A3BAAB15F376207BE6F771" xlink:to="loc_wlkp_CommonUnitsMember_01CE8C8DC2702F3A244976207BE755C2" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_SubordinatedUnitsMember" xlink:label="loc_wlkp_SubordinatedUnitsMember_2C96C4FAA6B387EF0A3976207BE771AF" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_924EC04506A3BAAB15F376207BE6F771" xlink:to="loc_wlkp_SubordinatedUnitsMember_2C96C4FAA6B387EF0A3976207BE771AF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_D5638D67212C9FB2AC2A76207BE7DE00" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_3E7415899A92287F152C76207BE6BA8F" xlink:to="loc_us-gaap_CounterpartyNameAxis_D5638D67212C9FB2AC2A76207BE7DE00" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_9F5F714A1FAFC6C2FFA176207BE7BD85_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_D5638D67212C9FB2AC2A76207BE7DE00" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_9F5F714A1FAFC6C2FFA176207BE7BD85_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_9F5F714A1FAFC6C2FFA176207BE7BD85" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_D5638D67212C9FB2AC2A76207BE7DE00" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_9F5F714A1FAFC6C2FFA176207BE7BD85" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_UnidentifiedThirdPartiesMember" xlink:label="loc_wlkp_UnidentifiedThirdPartiesMember_6F435D850ED7EA48C7C676207BE7912E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_9F5F714A1FAFC6C2FFA176207BE7BD85" xlink:to="loc_wlkp_UnidentifiedThirdPartiesMember_6F435D850ED7EA48C7C676207BE7912E" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_2273A985E2EF8607425576207BE7BAB5" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_9F5F714A1FAFC6C2FFA176207BE7BD85" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_2273A985E2EF8607425576207BE7BAB5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountUnitsIssued" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountUnitsIssued_083D8F2E0107029DD9AC76207BE71210" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_7301E855EF7D793D4E3676207BE76446" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountUnitsIssued_083D8F2E0107029DD9AC76207BE71210" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding_5F0093ABD82A733CDCA076207BE7FAA3" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_7301E855EF7D793D4E3676207BE76446" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding_5F0093ABD82A733CDCA076207BE7FAA3" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/ConsolidatedStatementsOfCashFlows" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/ConsolidatedStatementsOfChangesInEquity" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_3F7918DC045764F137FC1B9F3DF51E05" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_60231A52683E011D2B1B1B9F3DF3DB80" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_3F7918DC045764F137FC1B9F3DF51E05" xlink:to="loc_us-gaap_StatementTable_60231A52683E011D2B1B1B9F3DF3DB80" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_C2B0021AF1A7C6DCF7581B9F3DF32AEB" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_60231A52683E011D2B1B1B9F3DF3DB80" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_C2B0021AF1A7C6DCF7581B9F3DF32AEB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_C0206D8C860F1F5704FE1B9F3DF45706_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_C2B0021AF1A7C6DCF7581B9F3DF32AEB" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_C0206D8C860F1F5704FE1B9F3DF45706_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_C0206D8C860F1F5704FE1B9F3DF45706" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_C2B0021AF1A7C6DCF7581B9F3DF32AEB" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_C0206D8C860F1F5704FE1B9F3DF45706" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_CommonUnitsMember" xlink:label="loc_wlkp_CommonUnitsMember_6699AFA583AF14C375001B9F3DF4EDFC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_C0206D8C860F1F5704FE1B9F3DF45706" xlink:to="loc_wlkp_CommonUnitsMember_6699AFA583AF14C375001B9F3DF4EDFC" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_SubordinatedUnitsMember" xlink:label="loc_wlkp_SubordinatedUnitsMember_AACBCF0DAEEFC82707981B9F3DF4A93E" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_C0206D8C860F1F5704FE1B9F3DF45706" xlink:to="loc_wlkp_SubordinatedUnitsMember_AACBCF0DAEEFC82707981B9F3DF4A93E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_D4B1B94453D4E578B08C1B9F3DF43388" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_60231A52683E011D2B1B1B9F3DF3DB80" xlink:to="loc_us-gaap_CounterpartyNameAxis_D4B1B94453D4E578B08C1B9F3DF43388" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_11812662A8E728EFF6861B9F3DF4D9AF_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_D4B1B94453D4E578B08C1B9F3DF43388" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_11812662A8E728EFF6861B9F3DF4D9AF_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_11812662A8E728EFF6861B9F3DF4D9AF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_D4B1B94453D4E578B08C1B9F3DF43388" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_11812662A8E728EFF6861B9F3DF4D9AF" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_UnidentifiedThirdPartiesMember" xlink:label="loc_wlkp_UnidentifiedThirdPartiesMember_C121D09D35BDFA387EE21B9F3DF44B3A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_11812662A8E728EFF6861B9F3DF4D9AF" xlink:to="loc_wlkp_UnidentifiedThirdPartiesMember_C121D09D35BDFA387EE21B9F3DF44B3A" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_4A4E90467E27364385571B9F3DF47D46" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_11812662A8E728EFF6861B9F3DF4D9AF" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_4A4E90467E27364385571B9F3DF47D46" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_11C362A06B252D9644B31B9F3DF47028" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_60231A52683E011D2B1B1B9F3DF3DB80" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_11C362A06B252D9644B31B9F3DF47028" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_A54435C3F837FEFE9A991B9F3DF432D5_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_11C362A06B252D9644B31B9F3DF47028" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_A54435C3F837FEFE9A991B9F3DF432D5_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_A54435C3F837FEFE9A991B9F3DF432D5" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_11C362A06B252D9644B31B9F3DF47028" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_A54435C3F837FEFE9A991B9F3DF432D5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnerMember" xlink:label="loc_us-gaap_LimitedPartnerMember_729B660ACB4BE772632E1B9F3DF4FBBF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_A54435C3F837FEFE9A991B9F3DF432D5" xlink:to="loc_us-gaap_LimitedPartnerMember_729B660ACB4BE772632E1B9F3DF4FBBF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_GeneralPartnerMember" xlink:label="loc_us-gaap_GeneralPartnerMember_25A027A2B75FFFAA5F901B9F3DF4A260" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_A54435C3F837FEFE9A991B9F3DF432D5" xlink:to="loc_us-gaap_GeneralPartnerMember_25A027A2B75FFFAA5F901B9F3DF4A260" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_8E4998D366D5C094F3041B9F3DF470AD" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_60231A52683E011D2B1B1B9F3DF3DB80" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_8E4998D366D5C094F3041B9F3DF470AD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_27DE1580B5D327D34AC61B9F3DF4EDFA_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_8E4998D366D5C094F3041B9F3DF470AD" xlink:to="loc_us-gaap_EquityComponentDomain_27DE1580B5D327D34AC61B9F3DF4EDFA_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_27DE1580B5D327D34AC61B9F3DF4EDFA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_8E4998D366D5C094F3041B9F3DF470AD" xlink:to="loc_us-gaap_EquityComponentDomain_27DE1580B5D327D34AC61B9F3DF4EDFA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_8D18091AB18B23AD5F7A1B9F3DF59815" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_27DE1580B5D327D34AC61B9F3DF4EDFA" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_8D18091AB18B23AD5F7A1B9F3DF59815" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NoncontrollingInterestMember" xlink:label="loc_us-gaap_NoncontrollingInterestMember_506E6B9975532E51959D1B9F3DF512BA" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_27DE1580B5D327D34AC61B9F3DF4EDFA" xlink:to="loc_us-gaap_NoncontrollingInterestMember_506E6B9975532E51959D1B9F3DF512BA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_C7C7D6F308B9F09FC1261B9F3DF54875" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3F7918DC045764F137FC1B9F3DF51E05" xlink:to="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_C7C7D6F308B9F09FC1261B9F3DF54875" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_7485E6E3371A64E742711B9F3DF52A84" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3F7918DC045764F137FC1B9F3DF51E05" xlink:to="loc_us-gaap_ProfitLoss_7485E6E3371A64E742711B9F3DF52A84" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax_5D1295E51BD57DBA90C51B9F3DF50B3A" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3F7918DC045764F137FC1B9F3DF51E05" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax_5D1295E51BD57DBA90C51B9F3DF50B3A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountDistributionAmount" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountDistributionAmount_C74DDE82FA493A95E3A71B9F3DF58ACE" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3F7918DC045764F137FC1B9F3DF51E05" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountDistributionAmount_C74DDE82FA493A95E3A71B9F3DF58ACE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders" xlink:label="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_00C339F102777B4383211B9F3DF51E01" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3F7918DC045764F137FC1B9F3DF51E05" xlink:to="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_00C339F102777B4383211B9F3DF51E01" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/ConsolidatedStatementsOfComprehensiveIncome" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/ConsolidatedStatementsOfOperations" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_4A841CA573444685B3B9451984897F7B" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_1237C90CDB58A700DFFF45198489BFC9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_4A841CA573444685B3B9451984897F7B" xlink:to="loc_us-gaap_StatementTable_1237C90CDB58A700DFFF45198489BFC9" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_5D4EB1C9A9280513629245198489A4E3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_1237C90CDB58A700DFFF45198489BFC9" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_5D4EB1C9A9280513629245198489A4E3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_7A81CC857681CB49AD744519848958B1_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_5D4EB1C9A9280513629245198489A4E3" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_7A81CC857681CB49AD744519848958B1_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_7A81CC857681CB49AD744519848958B1" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_5D4EB1C9A9280513629245198489A4E3" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_7A81CC857681CB49AD744519848958B1" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_CommonUnitsMember" xlink:label="loc_wlkp_CommonUnitsMember_66DBA42C4F58B266D2F2451984893D6F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_7A81CC857681CB49AD744519848958B1" xlink:to="loc_wlkp_CommonUnitsMember_66DBA42C4F58B266D2F2451984893D6F" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_SubordinatedUnitsMember" xlink:label="loc_wlkp_SubordinatedUnitsMember_A59AE205257C4533A2B5451984899484" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_7A81CC857681CB49AD744519848958B1" xlink:to="loc_wlkp_SubordinatedUnitsMember_A59AE205257C4533A2B5451984899484" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_D7654F6E5E38E080135745198489814E" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_1237C90CDB58A700DFFF45198489BFC9" xlink:to="loc_us-gaap_CounterpartyNameAxis_D7654F6E5E38E080135745198489814E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_B54AFAB2EF48EFD75F8645198489CB30_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_D7654F6E5E38E080135745198489814E" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_B54AFAB2EF48EFD75F8645198489CB30_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_B54AFAB2EF48EFD75F8645198489CB30" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_D7654F6E5E38E080135745198489814E" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_B54AFAB2EF48EFD75F8645198489CB30" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_UnidentifiedThirdPartiesMember" xlink:label="loc_wlkp_UnidentifiedThirdPartiesMember_EA5FEAB9510EE7CCD7DA45198489849B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_B54AFAB2EF48EFD75F8645198489CB30" xlink:to="loc_wlkp_UnidentifiedThirdPartiesMember_EA5FEAB9510EE7CCD7DA45198489849B" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_E1919A43EB61163936F9451984894B24" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_B54AFAB2EF48EFD75F8645198489CB30" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_E1919A43EB61163936F9451984894B24" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RevenueFromRelatedParties" xlink:label="loc_us-gaap_RevenueFromRelatedParties_14762EF5C5E855B11BDA45198489DE3C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4A841CA573444685B3B9451984897F7B" xlink:to="loc_us-gaap_RevenueFromRelatedParties_14762EF5C5E855B11BDA45198489DE3C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherSalesRevenueNet" xlink:label="loc_us-gaap_OtherSalesRevenueNet_FB4E6E9AA38FCD150BBD45198489373C" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4A841CA573444685B3B9451984897F7B" xlink:to="loc_us-gaap_OtherSalesRevenueNet_FB4E6E9AA38FCD150BBD45198489373C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SalesRevenueNet" xlink:label="loc_us-gaap_SalesRevenueNet_D24B763ED1036684E3C1451984895790" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4A841CA573444685B3B9451984897F7B" xlink:to="loc_us-gaap_SalesRevenueNet_D24B763ED1036684E3C1451984895790" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CostOfGoodsSold" xlink:label="loc_us-gaap_CostOfGoodsSold_5E1C112B46F283CFBDFB451984898DD7" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4A841CA573444685B3B9451984897F7B" xlink:to="loc_us-gaap_CostOfGoodsSold_5E1C112B46F283CFBDFB451984898DD7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_GrossProfit" xlink:label="loc_us-gaap_GrossProfit_82CD7C0C058B16F45B0845198489B3B2" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4A841CA573444685B3B9451984897F7B" xlink:to="loc_us-gaap_GrossProfit_82CD7C0C058B16F45B0845198489B3B2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_0F3BECCB15E930CA292545198489F13C" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4A841CA573444685B3B9451984897F7B" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_0F3BECCB15E930CA292545198489F13C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_419C737C61844A08ACBF45198489FED8" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4A841CA573444685B3B9451984897F7B" xlink:to="loc_us-gaap_OperatingIncomeLoss_419C737C61844A08ACBF45198489FED8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NonoperatingIncomeExpenseAbstract" xlink:label="loc_us-gaap_NonoperatingIncomeExpenseAbstract_8DAEDA272A92872EC4344519848988A4" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4A841CA573444685B3B9451984897F7B" xlink:to="loc_us-gaap_NonoperatingIncomeExpenseAbstract_8DAEDA272A92872EC4344519848988A4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_InterestExpenseRelatedParty" xlink:label="loc_us-gaap_InterestExpenseRelatedParty_D0C9C19AB07CE49564B345198489E9FF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_8DAEDA272A92872EC4344519848988A4" xlink:to="loc_us-gaap_InterestExpenseRelatedParty_D0C9C19AB07CE49564B345198489E9FF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_7B38366F9AF8B908CD3A451984894B9A" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_8DAEDA272A92872EC4344519848988A4" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_7B38366F9AF8B908CD3A451984894B9A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_634F5E202F6D853DEC4945198489839E" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4A841CA573444685B3B9451984897F7B" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_634F5E202F6D853DEC4945198489839E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_FAEAF99919B4C3F34FE5451984897CFC" xlink:type="locator" />
    <definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4A841CA573444685B3B9451984897F7B" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_FAEAF99919B4C3F34FE5451984897CFC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_D3BC5BB8AD5B34765805451984898936" xlink:type="locator" />
    <definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4A841CA573444685B3B9451984897F7B" xlink:to="loc_us-gaap_ProfitLoss_D3BC5BB8AD5B34765805451984898936" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_A6486E4C310B0E575D61451984890548" xlink:type="locator" />
    <definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4A841CA573444685B3B9451984897F7B" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_A6486E4C310B0E575D61451984890548" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_F079866AFDC62998B7DC45198489666D" xlink:type="locator" />
    <definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4A841CA573444685B3B9451984897F7B" xlink:to="loc_us-gaap_NetIncomeLoss_F079866AFDC62998B7DC45198489666D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EarningsPerShareBasicAndDilutedAbstract" xlink:label="loc_us-gaap_EarningsPerShareBasicAndDilutedAbstract_3CE1E045E8B8791D34FB45198489B236" xlink:type="locator" />
    <definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4A841CA573444685B3B9451984897F7B" xlink:to="loc_us-gaap_EarningsPerShareBasicAndDilutedAbstract_3CE1E045E8B8791D34FB45198489B236" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EarningsPerShareBasicAndDiluted" xlink:label="loc_us-gaap_EarningsPerShareBasicAndDiluted_3EDCC3F0634E373243B345198489B730" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAndDilutedAbstract_3CE1E045E8B8791D34FB45198489B236" xlink:to="loc_us-gaap_EarningsPerShareBasicAndDiluted_3EDCC3F0634E373243B345198489B730" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract" xlink:label="loc_us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract_B2606A2560BCDD13FE62451984893E86" xlink:type="locator" />
    <definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4A841CA573444685B3B9451984897F7B" xlink:to="loc_us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract_B2606A2560BCDD13FE62451984893E86" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted" xlink:label="loc_us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted_253618EBD9014C40DD4545198489FDA8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract_B2606A2560BCDD13FE62451984893E86" xlink:to="loc_us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted_253618EBD9014C40DD4545198489FDA8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DistributionMadeToLimitedPartnerDistributionsPaidPerUnit" xlink:label="loc_us-gaap_DistributionMadeToLimitedPartnerDistributionsPaidPerUnit_2A60B2111E6F0026F8AE45198489DD0F" xlink:type="locator" />
    <definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4A841CA573444685B3B9451984897F7B" xlink:to="loc_us-gaap_DistributionMadeToLimitedPartnerDistributionsPaidPerUnit_2A60B2111E6F0026F8AE45198489DD0F" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/DerivativeInstruments" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/DerivativeInstrumentsDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DerivativeLineItems" xlink:label="loc_us-gaap_DerivativeLineItems_D91D9E2883DB5F30E27A467401A018F6" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DerivativeTable" xlink:label="loc_us-gaap_DerivativeTable_3ECCC2F173596E6F79234674019F0244" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_D91D9E2883DB5F30E27A467401A018F6" xlink:to="loc_us-gaap_DerivativeTable_3ECCC2F173596E6F79234674019F0244" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_C60267F8878EBEE581F14674019F651C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_3ECCC2F173596E6F79234674019F0244" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_C60267F8878EBEE581F14674019F651C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_D00584E11033E5FA28D0467401A0F419_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_C60267F8878EBEE581F14674019F651C" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_D00584E11033E5FA28D0467401A0F419_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_D00584E11033E5FA28D0467401A0F419" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_C60267F8878EBEE581F14674019F651C" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_D00584E11033E5FA28D0467401A0F419" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_InterestRateContractMember" xlink:label="loc_us-gaap_InterestRateContractMember_8238BA73C8D421254D57467401A0079E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_D00584E11033E5FA28D0467401A0F419" xlink:to="loc_us-gaap_InterestRateContractMember_8238BA73C8D421254D57467401A0079E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_HedgingDesignationAxis" xlink:label="loc_us-gaap_HedgingDesignationAxis_8C0DF242FCCF78BE9965467401A0DD63" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_3ECCC2F173596E6F79234674019F0244" xlink:to="loc_us-gaap_HedgingDesignationAxis_8C0DF242FCCF78BE9965467401A0DD63" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_803B650834595413FDB0467401A0B5CB_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_8C0DF242FCCF78BE9965467401A0DD63" xlink:to="loc_us-gaap_HedgingDesignationDomain_803B650834595413FDB0467401A0B5CB_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_803B650834595413FDB0467401A0B5CB" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_8C0DF242FCCF78BE9965467401A0DD63" xlink:to="loc_us-gaap_HedgingDesignationDomain_803B650834595413FDB0467401A0B5CB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_47E4FCC01355C57B7C73467401A080E1" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_3ECCC2F173596E6F79234674019F0244" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_47E4FCC01355C57B7C73467401A080E1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_44468353F52B69F97B53467401A0EA0E_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_47E4FCC01355C57B7C73467401A080E1" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_44468353F52B69F97B53467401A0EA0E_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_44468353F52B69F97B53467401A0EA0E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_47E4FCC01355C57B7C73467401A080E1" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_44468353F52B69F97B53467401A0EA0E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_InterestExpenseMember" xlink:label="loc_us-gaap_InterestExpenseMember_6136FC0DF5FFF892EE17467401A0EB05" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_44468353F52B69F97B53467401A0EA0E" xlink:to="loc_us-gaap_InterestExpenseMember_6136FC0DF5FFF892EE17467401A0EB05" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_0FFA33350899E197D8A8467401A09EDD" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_3ECCC2F173596E6F79234674019F0244" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_0FFA33350899E197D8A8467401A09EDD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_HedgingRelationshipDomain" xlink:label="loc_us-gaap_HedgingRelationshipDomain_DD4B7C9554D540A4E86D467401A0DEB2_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_0FFA33350899E197D8A8467401A09EDD" xlink:to="loc_us-gaap_HedgingRelationshipDomain_DD4B7C9554D540A4E86D467401A0DEB2_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_HedgingRelationshipDomain" xlink:label="loc_us-gaap_HedgingRelationshipDomain_DD4B7C9554D540A4E86D467401A0DEB2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_0FFA33350899E197D8A8467401A09EDD" xlink:to="loc_us-gaap_HedgingRelationshipDomain_DD4B7C9554D540A4E86D467401A0DEB2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CashFlowHedgingMember" xlink:label="loc_us-gaap_CashFlowHedgingMember_EA943FED14493B2AC21F467401A026D1" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_DD4B7C9554D540A4E86D467401A0DEB2" xlink:to="loc_us-gaap_CashFlowHedgingMember_EA943FED14493B2AC21F467401A026D1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_12ABB5A37DB4BD4F5743467401A009C4" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_3ECCC2F173596E6F79234674019F0244" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_12ABB5A37DB4BD4F5743467401A009C4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_BD2199C11560E65558A5467401A0AE3E_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_12ABB5A37DB4BD4F5743467401A009C4" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_BD2199C11560E65558A5467401A0AE3E_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_BD2199C11560E65558A5467401A0AE3E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_12ABB5A37DB4BD4F5743467401A009C4" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_BD2199C11560E65558A5467401A0AE3E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherAssetsMember" xlink:label="loc_us-gaap_OtherAssetsMember_8FAC600E3E1B02DBABC7467401A0FF33" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_BD2199C11560E65558A5467401A0AE3E" xlink:to="loc_us-gaap_OtherAssetsMember_8FAC600E3E1B02DBABC7467401A0FF33" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherLiabilitiesMember" xlink:label="loc_us-gaap_OtherLiabilitiesMember_C4AE3B44301012F796D9467401A074AD" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_BD2199C11560E65558A5467401A0AE3E" xlink:to="loc_us-gaap_OtherLiabilitiesMember_C4AE3B44301012F796D9467401A074AD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_InterestRateDerivativeAssetsAtFairValue" xlink:label="loc_us-gaap_InterestRateDerivativeAssetsAtFairValue_CD752C145741956E875E467401A0EDC2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_D91D9E2883DB5F30E27A467401A018F6" xlink:to="loc_us-gaap_InterestRateDerivativeAssetsAtFairValue_CD752C145741956E875E467401A0EDC2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_InterestRateDerivativeLiabilitiesAtFairValue" xlink:label="loc_us-gaap_InterestRateDerivativeLiabilitiesAtFairValue_48A8366378A6E402CD1E467401A01A01" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_D91D9E2883DB5F30E27A467401A018F6" xlink:to="loc_us-gaap_InterestRateDerivativeLiabilitiesAtFairValue_48A8366378A6E402CD1E467401A01A01" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DerivativeInstrumentsLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortion" xlink:label="loc_us-gaap_DerivativeInstrumentsLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortion_424729B8353D4CAC953C467401A0A2C8" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_D91D9E2883DB5F30E27A467401A018F6" xlink:to="loc_us-gaap_DerivativeInstrumentsLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortion_424729B8353D4CAC953C467401A0A2C8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNet" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNet_836A21D7DBDE2A7D5CCA4674049F4073" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_D91D9E2883DB5F30E27A467401A018F6" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNet_836A21D7DBDE2A7D5CCA4674049F4073" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossRecognizedInIncomeIneffectivePortionAndAmountExcludedFromEffectivenessTestingNet" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossRecognizedInIncomeIneffectivePortionAndAmountExcludedFromEffectivenessTestingNet_97C63F61AD1DF386AFB9467401A062DA" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_D91D9E2883DB5F30E27A467401A018F6" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossRecognizedInIncomeIneffectivePortionAndAmountExcludedFromEffectivenessTestingNet_97C63F61AD1DF386AFB9467401A062DA" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/DerivativeInstrumentsIneffectivePortionDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/DerivativeInstrumentsTables" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/DescriptionOfBusinessAndBasisOfPresentation" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/DescriptionOfBusinessAndBasisOfPresentationDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountLineItems" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_10AD9B471DFBACF186EF76207C3EB148" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable" xlink:label="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_22264C9B4775EE824EF176207C3DCB4C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_10AD9B471DFBACF186EF76207C3EB148" xlink:to="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_22264C9B4775EE824EF176207C3DCB4C" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_BA4497F429DA0149EE5676207C3D26DC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_22264C9B4775EE824EF176207C3DCB4C" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_BA4497F429DA0149EE5676207C3D26DC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_1051ACC59C9A16FADB3676207C3D6CC7_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_BA4497F429DA0149EE5676207C3D26DC" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_1051ACC59C9A16FADB3676207C3D6CC7_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_1051ACC59C9A16FADB3676207C3D6CC7" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_BA4497F429DA0149EE5676207C3D26DC" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_1051ACC59C9A16FADB3676207C3D6CC7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnerMember" xlink:label="loc_us-gaap_LimitedPartnerMember_6BD0DE6BCFAF5EBE69CC76207C3D9DE8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_1051ACC59C9A16FADB3676207C3D6CC7" xlink:to="loc_us-gaap_LimitedPartnerMember_6BD0DE6BCFAF5EBE69CC76207C3D9DE8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_9E627222A9B48501595F76207C3DF1B5" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_22264C9B4775EE824EF176207C3DCB4C" xlink:to="loc_dei_LegalEntityAxis_9E627222A9B48501595F76207C3DF1B5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_31BD622D8B2CAF60E14276207C3DAF59_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_9E627222A9B48501595F76207C3DF1B5" xlink:to="loc_dei_EntityDomain_31BD622D8B2CAF60E14276207C3DAF59_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_31BD622D8B2CAF60E14276207C3DAF59" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_9E627222A9B48501595F76207C3DF1B5" xlink:to="loc_dei_EntityDomain_31BD622D8B2CAF60E14276207C3DAF59" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_11DE2B1B846BA210A66676207C3D2245" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_31BD622D8B2CAF60E14276207C3DAF59" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_11DE2B1B846BA210A66676207C3D2245" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_WestlakeChemicalOpCoLPMember" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_8A7EA21DA50D660E44F576207C3DBA5A" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_31BD622D8B2CAF60E14276207C3DAF59" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_8A7EA21DA50D660E44F576207C3DBA5A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_F3D4DFDC1058571D2D7E76207C3DFD99" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_22264C9B4775EE824EF176207C3DCB4C" xlink:to="loc_us-gaap_CounterpartyNameAxis_F3D4DFDC1058571D2D7E76207C3DFD99" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_CB81CC99F264B2FD22ED76207C3DFA81_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_F3D4DFDC1058571D2D7E76207C3DFD99" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_CB81CC99F264B2FD22ED76207C3DFA81_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_CB81CC99F264B2FD22ED76207C3DFA81" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_F3D4DFDC1058571D2D7E76207C3DFD99" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_CB81CC99F264B2FD22ED76207C3DFA81" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_746C6A1ACB961931BB4476207C3E8EAC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_CB81CC99F264B2FD22ED76207C3DFA81" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_746C6A1ACB961931BB4476207C3E8EAC" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_WestlakeChemicalOpCoLPMember" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_86C7A5E5FD2B67AD642976207C3E6E26" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_CB81CC99F264B2FD22ED76207C3DFA81" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_86C7A5E5FD2B67AD642976207C3E6E26" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_WestlakeChemicalOpCoGPLLCMember" xlink:label="loc_wlkp_WestlakeChemicalOpCoGPLLCMember_8EAD7C3EE51AA17F9E0776207C3E8AA1" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_CB81CC99F264B2FD22ED76207C3DFA81" xlink:to="loc_wlkp_WestlakeChemicalOpCoGPLLCMember_8EAD7C3EE51AA17F9E0776207C3E8AA1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_A05B852023EDEBE92D5276207C3E8749" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_22264C9B4775EE824EF176207C3DCB4C" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_A05B852023EDEBE92D5276207C3E8749" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_8B01ED1A7A55B0D5D23976207C3ED3D9_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_A05B852023EDEBE92D5276207C3E8749" xlink:to="loc_us-gaap_RelatedPartyDomain_8B01ED1A7A55B0D5D23976207C3ED3D9_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_8B01ED1A7A55B0D5D23976207C3ED3D9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_A05B852023EDEBE92D5276207C3E8749" xlink:to="loc_us-gaap_RelatedPartyDomain_8B01ED1A7A55B0D5D23976207C3ED3D9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="loc_us-gaap_AffiliatedEntityMember_F59A19BACDA58E0A5C3876207C3E3E96" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_8B01ED1A7A55B0D5D23976207C3ED3D9" xlink:to="loc_us-gaap_AffiliatedEntityMember_F59A19BACDA58E0A5C3876207C3E3E96" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_WestlakeChemicalOpCoLPMember" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_0D0610A22C413A670A9176207C3E1A1B" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_8B01ED1A7A55B0D5D23976207C3ED3D9" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_0D0610A22C413A670A9176207C3E1A1B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedLiabilityCompanyMember" xlink:label="loc_us-gaap_LimitedLiabilityCompanyMember_61D8AF494BF833F0A8AC76207C3E4ABF" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_8B01ED1A7A55B0D5D23976207C3ED3D9" xlink:to="loc_us-gaap_LimitedLiabilityCompanyMember_61D8AF494BF833F0A8AC76207C3E4ABF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MajorityOwnedSubsidiaryUnconsolidatedMember" xlink:label="loc_us-gaap_MajorityOwnedSubsidiaryUnconsolidatedMember_54D16E1082A1ED0CE2B276207C3EFEF2" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_8B01ED1A7A55B0D5D23976207C3ED3D9" xlink:to="loc_us-gaap_MajorityOwnedSubsidiaryUnconsolidatedMember_54D16E1082A1ED0CE2B276207C3EFEF2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PartnersCapitalAccountUnitsSoldInPublicOffering" xlink:label="loc_us-gaap_PartnersCapitalAccountUnitsSoldInPublicOffering_5C2F173E191A3D48524676207C3E2517" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_10AD9B471DFBACF186EF76207C3EB148" xlink:to="loc_us-gaap_PartnersCapitalAccountUnitsSoldInPublicOffering_5C2F173E191A3D48524676207C3E2517" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest" xlink:label="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest_A0262175A29DAD2D528876207C3E0844" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_10AD9B471DFBACF186EF76207C3EB148" xlink:to="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest_A0262175A29DAD2D528876207C3E0844" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersAdditionalOwnershipInterest" xlink:label="loc_wlkp_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersAdditionalOwnershipInterest_723F44B45F06C606796076207C3E569E" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_10AD9B471DFBACF186EF76207C3EB148" xlink:to="loc_wlkp_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersAdditionalOwnershipInterest_723F44B45F06C606796076207C3E569E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PaymentsToAcquireLimitedPartnershipInterests" xlink:label="loc_us-gaap_PaymentsToAcquireLimitedPartnershipInterests_F2B707D3574CEBEB5C5576207C3FFC7C" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_10AD9B471DFBACF186EF76207C3EB148" xlink:to="loc_us-gaap_PaymentsToAcquireLimitedPartnershipInterests_F2B707D3574CEBEB5C5576207C3FFC7C" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_NumberofProductionFacilities" xlink:label="loc_wlkp_NumberofProductionFacilities_07ABE7513D7A97C6FB0C76207C3F93B7" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_10AD9B471DFBACF186EF76207C3EB148" xlink:to="loc_wlkp_NumberofProductionFacilities_07ABE7513D7A97C6FB0C76207C3F93B7" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/DescriptionOfBusinessAndBasisOfPresentationPolicies" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/DistributionsAndNetIncomePerLimitedPartnerUnit" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/DistributionsAndNetIncomePerLimitedPartnerUnitBasicAndDilutedIncomePerLimitedPartnerUnitDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountLineItems" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_ABDF6381432D1C97F4A176207C30119D" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable" xlink:label="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_E2165AB7DC83B219A62D76207C2F5AE5" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_ABDF6381432D1C97F4A176207C30119D" xlink:to="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_E2165AB7DC83B219A62D76207C2F5AE5" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis" xlink:label="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_58B7F5C3BDC76202BC1276207C2F36FF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_E2165AB7DC83B219A62D76207C2F5AE5" xlink:to="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_58B7F5C3BDC76202BC1276207C2F36FF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncentiveDistributionRecipientDomain" xlink:label="loc_us-gaap_IncentiveDistributionRecipientDomain_2651C228AFF9FEAEFBDC76207C30111A_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_58B7F5C3BDC76202BC1276207C2F36FF" xlink:to="loc_us-gaap_IncentiveDistributionRecipientDomain_2651C228AFF9FEAEFBDC76207C30111A_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncentiveDistributionRecipientDomain" xlink:label="loc_us-gaap_IncentiveDistributionRecipientDomain_2651C228AFF9FEAEFBDC76207C30111A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_58B7F5C3BDC76202BC1276207C2F36FF" xlink:to="loc_us-gaap_IncentiveDistributionRecipientDomain_2651C228AFF9FEAEFBDC76207C30111A" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_IDRHoldersMember" xlink:label="loc_wlkp_IDRHoldersMember_9AE899F6049C3683888276207C306E63" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncentiveDistributionRecipientDomain_2651C228AFF9FEAEFBDC76207C30111A" xlink:to="loc_wlkp_IDRHoldersMember_9AE899F6049C3683888276207C306E63" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_357891143798FFF3C1AD76207C309FF1" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_E2165AB7DC83B219A62D76207C2F5AE5" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_357891143798FFF3C1AD76207C309FF1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_71F692BA8D37BDB7B6FE76207C300D18_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_357891143798FFF3C1AD76207C309FF1" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_71F692BA8D37BDB7B6FE76207C300D18_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_71F692BA8D37BDB7B6FE76207C300D18" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_357891143798FFF3C1AD76207C309FF1" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_71F692BA8D37BDB7B6FE76207C300D18" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_CommonUnitsMember" xlink:label="loc_wlkp_CommonUnitsMember_1F174C0B9997932D9C2276207C30134C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_71F692BA8D37BDB7B6FE76207C300D18" xlink:to="loc_wlkp_CommonUnitsMember_1F174C0B9997932D9C2276207C30134C" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_SubordinatedUnitsMember" xlink:label="loc_wlkp_SubordinatedUnitsMember_F065EFB3C29FCA96785576207C30791B" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_71F692BA8D37BDB7B6FE76207C300D18" xlink:to="loc_wlkp_SubordinatedUnitsMember_F065EFB3C29FCA96785576207C30791B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DistributedEarnings" xlink:label="loc_us-gaap_DistributedEarnings_4FFBBB81C33B0191469276207C3049EB" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_ABDF6381432D1C97F4A176207C30119D" xlink:to="loc_us-gaap_DistributedEarnings_4FFBBB81C33B0191469276207C3049EB" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_IncentiveDistributionSubsequentDistributionAmount" xlink:label="loc_wlkp_IncentiveDistributionSubsequentDistributionAmount_76E5A76C223C1226164576207C30AB0F" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_ABDF6381432D1C97F4A176207C30119D" xlink:to="loc_wlkp_IncentiveDistributionSubsequentDistributionAmount_76E5A76C223C1226164576207C30AB0F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UndistributedEarnings" xlink:label="loc_us-gaap_UndistributedEarnings_5DC388DB86418DE0829E76207C3023B5" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_ABDF6381432D1C97F4A176207C30119D" xlink:to="loc_us-gaap_UndistributedEarnings_5DC388DB86418DE0829E76207C3023B5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_1F61E7642F6F13969C6276207C301E90" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_ABDF6381432D1C97F4A176207C30119D" xlink:to="loc_us-gaap_NetIncomeLoss_1F61E7642F6F13969C6276207C301E90" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract" xlink:label="loc_us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract_09C49277160019B31AF476207C30C20E" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_ABDF6381432D1C97F4A176207C30119D" xlink:to="loc_us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract_09C49277160019B31AF476207C30C20E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted" xlink:label="loc_us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted_C2E21DCF1BE2EABB480476207C305FD6" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract_09C49277160019B31AF476207C30C20E" xlink:to="loc_us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted_C2E21DCF1BE2EABB480476207C305FD6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EarningsPerShareBasicAndDilutedAbstract" xlink:label="loc_us-gaap_EarningsPerShareBasicAndDilutedAbstract_001561EE9174F702622276207C303733" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_ABDF6381432D1C97F4A176207C30119D" xlink:to="loc_us-gaap_EarningsPerShareBasicAndDilutedAbstract_001561EE9174F702622276207C303733" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EarningsPerShareBasicAndDiluted" xlink:label="loc_us-gaap_EarningsPerShareBasicAndDiluted_BB83AD8513F27723DBBF76207C31F985" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAndDilutedAbstract_001561EE9174F702622276207C303733" xlink:to="loc_us-gaap_EarningsPerShareBasicAndDiluted_BB83AD8513F27723DBBF76207C31F985" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/DistributionsAndNetIncomePerLimitedPartnerUnitDistributionsDeclaredDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DistributionMadeToLimitedPartnerLineItems" xlink:label="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_6ACDBFC07BFA53316F5A1B9F3D8379A7" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DistributionsMadeToLimitedPartnerTable" xlink:label="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_4FFAED694306FDBC5F851B9F3D784F60" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_6ACDBFC07BFA53316F5A1B9F3D8379A7" xlink:to="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_4FFAED694306FDBC5F851B9F3D784F60" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis" xlink:label="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_8D5C9FBE8571A6EF40B41B9F3D81AC34" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_4FFAED694306FDBC5F851B9F3D784F60" xlink:to="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_8D5C9FBE8571A6EF40B41B9F3D81AC34" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DistributionTypeDomain" xlink:label="loc_us-gaap_DistributionTypeDomain_8E2B9FD8893D6E1CC86F1B9F3D81706C_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_8D5C9FBE8571A6EF40B41B9F3D81AC34" xlink:to="loc_us-gaap_DistributionTypeDomain_8E2B9FD8893D6E1CC86F1B9F3D81706C_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DistributionTypeDomain" xlink:label="loc_us-gaap_DistributionTypeDomain_8E2B9FD8893D6E1CC86F1B9F3D81706C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_8D5C9FBE8571A6EF40B41B9F3D81AC34" xlink:to="loc_us-gaap_DistributionTypeDomain_8E2B9FD8893D6E1CC86F1B9F3D81706C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CashDistributionMember" xlink:label="loc_us-gaap_CashDistributionMember_1A742ACA591E7BCB1B081B9F3D81DD78" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionTypeDomain_8E2B9FD8893D6E1CC86F1B9F3D81706C" xlink:to="loc_us-gaap_CashDistributionMember_1A742ACA591E7BCB1B081B9F3D81DD78" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_CashDistributionTrancheOneMember" xlink:label="loc_wlkp_CashDistributionTrancheOneMember_13B765C24486734AC9711B9F3D81D03F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashDistributionMember_1A742ACA591E7BCB1B081B9F3D81DD78" xlink:to="loc_wlkp_CashDistributionTrancheOneMember_13B765C24486734AC9711B9F3D81D03F" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_CashDistributionTrancheTwoMember" xlink:label="loc_wlkp_CashDistributionTrancheTwoMember_7BED647CD1B57BD2B6B21B9F3D81680B" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashDistributionMember_1A742ACA591E7BCB1B081B9F3D81DD78" xlink:to="loc_wlkp_CashDistributionTrancheTwoMember_7BED647CD1B57BD2B6B21B9F3D81680B" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_CashDistributionTrancheThreeMember" xlink:label="loc_wlkp_CashDistributionTrancheThreeMember_DD0CB1258E11CA45A3D71B9F3D81E82F" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashDistributionMember_1A742ACA591E7BCB1B081B9F3D81DD78" xlink:to="loc_wlkp_CashDistributionTrancheThreeMember_DD0CB1258E11CA45A3D71B9F3D81E82F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_AC03B199B5B16609C0A61B9F3D810663" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_4FFAED694306FDBC5F851B9F3D784F60" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_AC03B199B5B16609C0A61B9F3D810663" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_F86BD293B2645BB7F8901B9F3D82177F_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_AC03B199B5B16609C0A61B9F3D810663" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_F86BD293B2645BB7F8901B9F3D82177F_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_F86BD293B2645BB7F8901B9F3D82177F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_AC03B199B5B16609C0A61B9F3D810663" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_F86BD293B2645BB7F8901B9F3D82177F" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_CommonUnitsMember" xlink:label="loc_wlkp_CommonUnitsMember_E91BEBCE68AE59436E181B9F3D82585A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_F86BD293B2645BB7F8901B9F3D82177F" xlink:to="loc_wlkp_CommonUnitsMember_E91BEBCE68AE59436E181B9F3D82585A" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_SubordinatedUnitsMember" xlink:label="loc_wlkp_SubordinatedUnitsMember_239836AA75FC848F9E011B9F3D8291BE" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_F86BD293B2645BB7F8901B9F3D82177F" xlink:to="loc_wlkp_SubordinatedUnitsMember_239836AA75FC848F9E011B9F3D8291BE" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_CommonAndSubordinatedUnitsMember" xlink:label="loc_wlkp_CommonAndSubordinatedUnitsMember_D7D9D8EC22D37DC0D1201B9F3D823D02" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_F86BD293B2645BB7F8901B9F3D82177F" xlink:to="loc_wlkp_CommonAndSubordinatedUnitsMember_D7D9D8EC22D37DC0D1201B9F3D823D02" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis" xlink:label="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_B7398BCF25ED8E9D22CF1B9F3D82B6C0" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_4FFAED694306FDBC5F851B9F3D784F60" xlink:to="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_B7398BCF25ED8E9D22CF1B9F3D82B6C0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncentiveDistributionRecipientDomain" xlink:label="loc_us-gaap_IncentiveDistributionRecipientDomain_5949ED1A0D77BC9A94521B9F3D829503_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_B7398BCF25ED8E9D22CF1B9F3D82B6C0" xlink:to="loc_us-gaap_IncentiveDistributionRecipientDomain_5949ED1A0D77BC9A94521B9F3D829503_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncentiveDistributionRecipientDomain" xlink:label="loc_us-gaap_IncentiveDistributionRecipientDomain_5949ED1A0D77BC9A94521B9F3D829503" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_B7398BCF25ED8E9D22CF1B9F3D82B6C0" xlink:to="loc_us-gaap_IncentiveDistributionRecipientDomain_5949ED1A0D77BC9A94521B9F3D829503" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_IDRHoldersMember" xlink:label="loc_wlkp_IDRHoldersMember_9D46B1E05D676CC3B40E1B9F3D82BB77" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncentiveDistributionRecipientDomain_5949ED1A0D77BC9A94521B9F3D829503" xlink:to="loc_wlkp_IDRHoldersMember_9D46B1E05D676CC3B40E1B9F3D82BB77" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_UnitHoldersMember" xlink:label="loc_wlkp_UnitHoldersMember_BBEAB163179B030FDFE81B9F3D8314F7" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncentiveDistributionRecipientDomain_5949ED1A0D77BC9A94521B9F3D829503" xlink:to="loc_wlkp_UnitHoldersMember_BBEAB163179B030FDFE81B9F3D8314F7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_664B86C3C87CB04489A61B9F3D830DE2" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_4FFAED694306FDBC5F851B9F3D784F60" xlink:to="loc_us-gaap_RangeAxis_664B86C3C87CB04489A61B9F3D830DE2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_8B259B042F220A129E171B9F3D83A40F_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_664B86C3C87CB04489A61B9F3D830DE2" xlink:to="loc_us-gaap_RangeMember_8B259B042F220A129E171B9F3D83A40F_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_8B259B042F220A129E171B9F3D83A40F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_664B86C3C87CB04489A61B9F3D830DE2" xlink:to="loc_us-gaap_RangeMember_8B259B042F220A129E171B9F3D83A40F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_FFF4C8968FE8473CB0D31B9F3D833F16" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_8B259B042F220A129E171B9F3D83A40F" xlink:to="loc_us-gaap_MinimumMember_FFF4C8968FE8473CB0D31B9F3D833F16" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_F05EC2D3FF6CA814D67A1B9F3D83E458" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_8B259B042F220A129E171B9F3D83A40F" xlink:to="loc_us-gaap_MaximumMember_F05EC2D3FF6CA814D67A1B9F3D83E458" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_CF33F5D77E6179F2E8321B9F3D83EC5A" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_4FFAED694306FDBC5F851B9F3D784F60" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_CF33F5D77E6179F2E8321B9F3D83EC5A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_F4FA7AF8C9C26DB3FE0E1B9F3D834532_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_CF33F5D77E6179F2E8321B9F3D83EC5A" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_F4FA7AF8C9C26DB3FE0E1B9F3D834532_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_F4FA7AF8C9C26DB3FE0E1B9F3D834532" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_CF33F5D77E6179F2E8321B9F3D83EC5A" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_F4FA7AF8C9C26DB3FE0E1B9F3D834532" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaap_SubsequentEventMember_5129DEABBC323B3F0EBB1B9F3D83CC10" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_F4FA7AF8C9C26DB3FE0E1B9F3D834532" xlink:to="loc_us-gaap_SubsequentEventMember_5129DEABBC323B3F0EBB1B9F3D83CC10" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit" xlink:label="loc_us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit_E82DF017272615CEF9891B9F3D83B7E2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_6ACDBFC07BFA53316F5A1B9F3D8379A7" xlink:to="loc_us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit_E82DF017272615CEF9891B9F3D83B7E2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncentiveDistributionDistributionPerYear" xlink:label="loc_us-gaap_IncentiveDistributionDistributionPerYear_12664D5C236B35039BDF1B9F3D8378B5" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_6ACDBFC07BFA53316F5A1B9F3D8379A7" xlink:to="loc_us-gaap_IncentiveDistributionDistributionPerYear_12664D5C236B35039BDF1B9F3D8378B5" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_MinimumQuarterlyDistributionPerUnit" xlink:label="loc_wlkp_MinimumQuarterlyDistributionPerUnit_5ADC18F11B998946AC551B9F3D83E278" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_6ACDBFC07BFA53316F5A1B9F3D8379A7" xlink:to="loc_wlkp_MinimumQuarterlyDistributionPerUnit_5ADC18F11B998946AC551B9F3D83E278" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_IncentiveDistributionMarginalPercentageInterestinDistributions" xlink:label="loc_wlkp_IncentiveDistributionMarginalPercentageInterestinDistributions_D93B7C1E214F4EFA0E491B9F3D830965" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_6ACDBFC07BFA53316F5A1B9F3D8379A7" xlink:to="loc_wlkp_IncentiveDistributionMarginalPercentageInterestinDistributions_D93B7C1E214F4EFA0E491B9F3D830965" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_IncentiveDistributionRightsTargetDistributionPerUnitRequiringMarginalPercentageDistributiontoIDRHolders" xlink:label="loc_wlkp_IncentiveDistributionRightsTargetDistributionPerUnitRequiringMarginalPercentageDistributiontoIDRHolders_5DEB954FA0E23DE4E66B1B9F3D83CAAE" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_6ACDBFC07BFA53316F5A1B9F3D8379A7" xlink:to="loc_wlkp_IncentiveDistributionRightsTargetDistributionPerUnitRequiringMarginalPercentageDistributiontoIDRHolders_5DEB954FA0E23DE4E66B1B9F3D83CAAE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_7AFA92A03849AFF88F3E1B9F3D83FCB6" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_6ACDBFC07BFA53316F5A1B9F3D8379A7" xlink:to="loc_us-gaap_NetIncomeLoss_7AFA92A03849AFF88F3E1B9F3D83FCB6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DistributedEarnings" xlink:label="loc_us-gaap_DistributedEarnings_287731C6A2929B2614F81B9F3D83DF29" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_6ACDBFC07BFA53316F5A1B9F3D8379A7" xlink:to="loc_us-gaap_DistributedEarnings_287731C6A2929B2614F81B9F3D83DF29" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_IncentiveDistributionSubsequentDistributionAmount" xlink:label="loc_wlkp_IncentiveDistributionSubsequentDistributionAmount_DA04919BF1A2203FDBED1B9F3D834778" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_6ACDBFC07BFA53316F5A1B9F3D8379A7" xlink:to="loc_wlkp_IncentiveDistributionSubsequentDistributionAmount_DA04919BF1A2203FDBED1B9F3D834778" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UndistributedEarnings" xlink:label="loc_us-gaap_UndistributedEarnings_C38B982C981F3C5126121B9F3D84E37E" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_6ACDBFC07BFA53316F5A1B9F3D8379A7" xlink:to="loc_us-gaap_UndistributedEarnings_C38B982C981F3C5126121B9F3D84E37E" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_IncentiveDistributionQuarterlyDistributionPerUnitDistributionThreshold" xlink:label="loc_wlkp_IncentiveDistributionQuarterlyDistributionPerUnitDistributionThreshold_A2BC6C299FD0B7F3D0C51B9F3D844E4F" xlink:type="locator" />
    <definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_6ACDBFC07BFA53316F5A1B9F3D8379A7" xlink:to="loc_wlkp_IncentiveDistributionQuarterlyDistributionPerUnitDistributionThreshold_A2BC6C299FD0B7F3D0C51B9F3D844E4F" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/DistributionsAndNetIncomePerLimitedPartnerUnitIncomeInExcessOfDistributionDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerLineItems" xlink:label="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerLineItems_99875C9B5BE2000E5A5876207C248CC8" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfIncentiveDistributionMadeToManagingMemberOrGeneralPartnerTable" xlink:label="loc_us-gaap_ScheduleOfIncentiveDistributionMadeToManagingMemberOrGeneralPartnerTable_6D06ABB4575F7AA67C8476207C239715" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerLineItems_99875C9B5BE2000E5A5876207C248CC8" xlink:to="loc_us-gaap_ScheduleOfIncentiveDistributionMadeToManagingMemberOrGeneralPartnerTable_6D06ABB4575F7AA67C8476207C239715" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis" xlink:label="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_19A61D3BCE0728A392C676207C23AA6F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfIncentiveDistributionMadeToManagingMemberOrGeneralPartnerTable_6D06ABB4575F7AA67C8476207C239715" xlink:to="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_19A61D3BCE0728A392C676207C23AA6F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DistributionTypeDomain" xlink:label="loc_us-gaap_DistributionTypeDomain_8FB73976070CB8F82C7C76207C24509C_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_19A61D3BCE0728A392C676207C23AA6F" xlink:to="loc_us-gaap_DistributionTypeDomain_8FB73976070CB8F82C7C76207C24509C_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DistributionTypeDomain" xlink:label="loc_us-gaap_DistributionTypeDomain_8FB73976070CB8F82C7C76207C24509C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_19A61D3BCE0728A392C676207C23AA6F" xlink:to="loc_us-gaap_DistributionTypeDomain_8FB73976070CB8F82C7C76207C24509C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CashDistributionMember" xlink:label="loc_us-gaap_CashDistributionMember_621CAA7766AEDE8F035A76207C24BB7F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionTypeDomain_8FB73976070CB8F82C7C76207C24509C" xlink:to="loc_us-gaap_CashDistributionMember_621CAA7766AEDE8F035A76207C24BB7F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_35B214D8770DADAEA8B976207C240002" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfIncentiveDistributionMadeToManagingMemberOrGeneralPartnerTable_6D06ABB4575F7AA67C8476207C239715" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_35B214D8770DADAEA8B976207C240002" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_1138CD843ED5610C004F76207C2463A4_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_35B214D8770DADAEA8B976207C240002" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_1138CD843ED5610C004F76207C2463A4_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_1138CD843ED5610C004F76207C2463A4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_35B214D8770DADAEA8B976207C240002" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_1138CD843ED5610C004F76207C2463A4" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_CommonUnitsMember" xlink:label="loc_wlkp_CommonUnitsMember_BBF60B8DAC97FD0AE81D76207C249CD9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_1138CD843ED5610C004F76207C2463A4" xlink:to="loc_wlkp_CommonUnitsMember_BBF60B8DAC97FD0AE81D76207C249CD9" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_SubordinatedUnitsMember" xlink:label="loc_wlkp_SubordinatedUnitsMember_E5ECCB8842591F3059C676207C24F384" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_1138CD843ED5610C004F76207C2463A4" xlink:to="loc_wlkp_SubordinatedUnitsMember_E5ECCB8842591F3059C676207C24F384" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis" xlink:label="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_E7459967C7FB3A57237A76207C2463A5" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfIncentiveDistributionMadeToManagingMemberOrGeneralPartnerTable_6D06ABB4575F7AA67C8476207C239715" xlink:to="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_E7459967C7FB3A57237A76207C2463A5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncentiveDistributionRecipientDomain" xlink:label="loc_us-gaap_IncentiveDistributionRecipientDomain_B3B409C8F558F2B824BC76207C24EFEB_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_E7459967C7FB3A57237A76207C2463A5" xlink:to="loc_us-gaap_IncentiveDistributionRecipientDomain_B3B409C8F558F2B824BC76207C24EFEB_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncentiveDistributionRecipientDomain" xlink:label="loc_us-gaap_IncentiveDistributionRecipientDomain_B3B409C8F558F2B824BC76207C24EFEB" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_E7459967C7FB3A57237A76207C2463A5" xlink:to="loc_us-gaap_IncentiveDistributionRecipientDomain_B3B409C8F558F2B824BC76207C24EFEB" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_IDRHoldersMember" xlink:label="loc_wlkp_IDRHoldersMember_A18FB0CC365B7BA3F4FD76207C24292A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncentiveDistributionRecipientDomain_B3B409C8F558F2B824BC76207C24EFEB" xlink:to="loc_wlkp_IDRHoldersMember_A18FB0CC365B7BA3F4FD76207C24292A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_4F27DAE5D92B1D79757A76207C24B574" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerLineItems_99875C9B5BE2000E5A5876207C248CC8" xlink:to="loc_us-gaap_NetIncomeLoss_4F27DAE5D92B1D79757A76207C24B574" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DistributedEarnings" xlink:label="loc_us-gaap_DistributedEarnings_5D7AF332CFBB2BFA12B276207C24510A" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerLineItems_99875C9B5BE2000E5A5876207C248CC8" xlink:to="loc_us-gaap_DistributedEarnings_5D7AF332CFBB2BFA12B276207C24510A" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_IncentiveDistributionSubsequentDistributionAmount" xlink:label="loc_wlkp_IncentiveDistributionSubsequentDistributionAmount_318A5F19E3D05D92A73476207C246AFF" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerLineItems_99875C9B5BE2000E5A5876207C248CC8" xlink:to="loc_wlkp_IncentiveDistributionSubsequentDistributionAmount_318A5F19E3D05D92A73476207C246AFF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UndistributedEarnings" xlink:label="loc_us-gaap_UndistributedEarnings_428728EF16732B0BC85A76207C244F98" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerLineItems_99875C9B5BE2000E5A5876207C248CC8" xlink:to="loc_us-gaap_UndistributedEarnings_428728EF16732B0BC85A76207C244F98" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/DistributionsAndNetIncomePerLimitedPartnerUnitTables" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/DocumentAndEntityInformation" xlink:type="extended">
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentInformationLineItems" xlink:label="loc_dei_DocumentInformationLineItems_11C4F58DC7EF46A2D80476207B9FB89A" xlink:type="locator" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentInformationTable" xlink:label="loc_dei_DocumentInformationTable_8120137BE70BEA1599D976207B9E19E8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_DocumentInformationLineItems_11C4F58DC7EF46A2D80476207B9FB89A" xlink:to="loc_dei_DocumentInformationTable_8120137BE70BEA1599D976207B9E19E8" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_5CD531B07D221637524676207B9ECF5A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_DocumentInformationTable_8120137BE70BEA1599D976207B9E19E8" xlink:to="loc_us-gaap_StatementClassOfStockAxis_5CD531B07D221637524676207B9ECF5A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_FB3D75FCDA48870863C976207B9E1BCC_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_5CD531B07D221637524676207B9ECF5A" xlink:to="loc_us-gaap_ClassOfStockDomain_FB3D75FCDA48870863C976207B9E1BCC_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_FB3D75FCDA48870863C976207B9E1BCC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_5CD531B07D221637524676207B9ECF5A" xlink:to="loc_us-gaap_ClassOfStockDomain_FB3D75FCDA48870863C976207B9E1BCC" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_CommonUnitsMember" xlink:label="loc_wlkp_CommonUnitsMember_5E995A08590BD6D710F976207B9E4445" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_FB3D75FCDA48870863C976207B9E1BCC" xlink:to="loc_wlkp_CommonUnitsMember_5E995A08590BD6D710F976207B9E4445" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_SubordinatedUnitsMember" xlink:label="loc_wlkp_SubordinatedUnitsMember_F85AC474BDF85083257D76207B9F7023" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_FB3D75FCDA48870863C976207B9E1BCC" xlink:to="loc_wlkp_SubordinatedUnitsMember_F85AC474BDF85083257D76207B9F7023" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentType" xlink:label="loc_dei_DocumentType_87B6909481ABF2A4188376207B9F2F9E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_11C4F58DC7EF46A2D80476207B9FB89A" xlink:to="loc_dei_DocumentType_87B6909481ABF2A4188376207B9F2F9E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_AmendmentFlag" xlink:label="loc_dei_AmendmentFlag_E9E8FF022E80031A52F676207B9F29F0" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_11C4F58DC7EF46A2D80476207B9FB89A" xlink:to="loc_dei_AmendmentFlag_E9E8FF022E80031A52F676207B9F29F0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentPeriodEndDate" xlink:label="loc_dei_DocumentPeriodEndDate_C7C9EB5A96B5B2FA46F276207B9F76E3" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_11C4F58DC7EF46A2D80476207B9FB89A" xlink:to="loc_dei_DocumentPeriodEndDate_C7C9EB5A96B5B2FA46F276207B9F76E3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentFiscalYearFocus" xlink:label="loc_dei_DocumentFiscalYearFocus_B5F601F21B3A7509DE1E76207B9F2DBE" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_11C4F58DC7EF46A2D80476207B9FB89A" xlink:to="loc_dei_DocumentFiscalYearFocus_B5F601F21B3A7509DE1E76207B9F2DBE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentFiscalPeriodFocus" xlink:label="loc_dei_DocumentFiscalPeriodFocus_B8AFE6B3E678DD0DF6F076207B9FF461" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_11C4F58DC7EF46A2D80476207B9FB89A" xlink:to="loc_dei_DocumentFiscalPeriodFocus_B8AFE6B3E678DD0DF6F076207B9FF461" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_TradingSymbol" xlink:label="loc_dei_TradingSymbol_CB73CFC9135FA41F966876207B9FE73E" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_11C4F58DC7EF46A2D80476207B9FB89A" xlink:to="loc_dei_TradingSymbol_CB73CFC9135FA41F966876207B9FE73E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityRegistrantName" xlink:label="loc_dei_EntityRegistrantName_11C6B1C6E532EAF4728676207B9FA7E2" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_11C4F58DC7EF46A2D80476207B9FB89A" xlink:to="loc_dei_EntityRegistrantName_11C6B1C6E532EAF4728676207B9FA7E2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityCentralIndexKey" xlink:label="loc_dei_EntityCentralIndexKey_16F6928DC301531FA73476207B9F4332" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_11C4F58DC7EF46A2D80476207B9FB89A" xlink:to="loc_dei_EntityCentralIndexKey_16F6928DC301531FA73476207B9F4332" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_CurrentFiscalYearEndDate" xlink:label="loc_dei_CurrentFiscalYearEndDate_241F36A19C5457D7A1EF76207B9F7BDB" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_11C4F58DC7EF46A2D80476207B9FB89A" xlink:to="loc_dei_CurrentFiscalYearEndDate_241F36A19C5457D7A1EF76207B9F7BDB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityFilerCategory" xlink:label="loc_dei_EntityFilerCategory_E316DE313DB09B2C1EE276207B9F1F7D" xlink:type="locator" />
    <definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_11C4F58DC7EF46A2D80476207B9FB89A" xlink:to="loc_dei_EntityFilerCategory_E316DE313DB09B2C1EE276207B9F1F7D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityCommonStockSharesOutstanding" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_64A7F2700A553EEB56DD76207B9F5B49" xlink:type="locator" />
    <definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_11C4F58DC7EF46A2D80476207B9FB89A" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_64A7F2700A553EEB56DD76207B9F5B49" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/FairValueMeasurements" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/FairValueMeasurementsSummaryOfAssetsAndLiabilitiesAccountedAtFairValueOnRecurringAndNonrecurringBasisDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_0F6C40389D92C1F3DEA31B9F3BF7EB37" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_5CE90B8B363BF050DD8B1B9F3BF66698" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_0F6C40389D92C1F3DEA31B9F3BF7EB37" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_5CE90B8B363BF050DD8B1B9F3BF66698" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_DCFDAF189CF2E7F5A75C1B9F3BF7CE1C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_5CE90B8B363BF050DD8B1B9F3BF66698" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_DCFDAF189CF2E7F5A75C1B9F3BF7CE1C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_A73128FABEC3DD6353081B9F3BF7E8FE_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_DCFDAF189CF2E7F5A75C1B9F3BF7CE1C" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_A73128FABEC3DD6353081B9F3BF7E8FE_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_A73128FABEC3DD6353081B9F3BF7E8FE" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_DCFDAF189CF2E7F5A75C1B9F3BF7CE1C" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_A73128FABEC3DD6353081B9F3BF7E8FE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_E038570E1C350C0696CF1B9F3BF7D661" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_A73128FABEC3DD6353081B9F3BF7E8FE" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_E038570E1C350C0696CF1B9F3BF7D661" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_DB96860FC1D9A6AA58C71B9F3BF60104" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_5CE90B8B363BF050DD8B1B9F3BF66698" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_DB96860FC1D9A6AA58C71B9F3BF60104" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_D4255E5E10A2E77C0B3E1B9F3BF61487_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_DB96860FC1D9A6AA58C71B9F3BF60104" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_D4255E5E10A2E77C0B3E1B9F3BF61487_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_D4255E5E10A2E77C0B3E1B9F3BF61487" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_DB96860FC1D9A6AA58C71B9F3BF60104" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_D4255E5E10A2E77C0B3E1B9F3BF61487" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_InterestRateContractMember" xlink:label="loc_us-gaap_InterestRateContractMember_884C2132384BA544278F1B9F3BF68321" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_D4255E5E10A2E77C0B3E1B9F3BF61487" xlink:to="loc_us-gaap_InterestRateContractMember_884C2132384BA544278F1B9F3BF68321" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_AF3B2BC3BBF996823F461B9F3BF78EBD" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_5CE90B8B363BF050DD8B1B9F3BF66698" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_AF3B2BC3BBF996823F461B9F3BF78EBD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_657904181A7808B0733A1B9F3BF7126F_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_AF3B2BC3BBF996823F461B9F3BF78EBD" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_657904181A7808B0733A1B9F3BF7126F_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_657904181A7808B0733A1B9F3BF7126F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_AF3B2BC3BBF996823F461B9F3BF78EBD" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_657904181A7808B0733A1B9F3BF7126F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_A101EE240A2F5E9669641B9F3BF77593" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_657904181A7808B0733A1B9F3BF7126F" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_A101EE240A2F5E9669641B9F3BF77593" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_InterestRateDerivativeLiabilitiesAtFairValue" xlink:label="loc_us-gaap_InterestRateDerivativeLiabilitiesAtFairValue_821789DE8C63AD1599091B9F3BF7D811" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_0F6C40389D92C1F3DEA31B9F3BF7EB37" xlink:to="loc_us-gaap_InterestRateDerivativeLiabilitiesAtFairValue_821789DE8C63AD1599091B9F3BF7D811" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_InterestRateDerivativeAssetsAtFairValue" xlink:label="loc_us-gaap_InterestRateDerivativeAssetsAtFairValue_EE0E5939A534D142C80D1B9F3BF76862" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_0F6C40389D92C1F3DEA31B9F3BF7EB37" xlink:to="loc_us-gaap_InterestRateDerivativeAssetsAtFairValue_EE0E5939A534D142C80D1B9F3BF76862" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/FairValueMeasurementsSummaryOfCarryingAndFairValuesOfLongTermDebtDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_8D22B7097164F8F960F91B9F3BF2C857" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_D9E7EAA1729E708481A21B9F3BF1277C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_8D22B7097164F8F960F91B9F3BF2C857" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_D9E7EAA1729E708481A21B9F3BF1277C" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_52ED52AC4D6D50C318E21B9F3BF137CE" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_D9E7EAA1729E708481A21B9F3BF1277C" xlink:to="loc_us-gaap_DebtInstrumentAxis_52ED52AC4D6D50C318E21B9F3BF137CE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_B2679AEF0C551370EAB71B9F3BF1241F_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_52ED52AC4D6D50C318E21B9F3BF137CE" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_B2679AEF0C551370EAB71B9F3BF1241F_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_B2679AEF0C551370EAB71B9F3BF1241F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_52ED52AC4D6D50C318E21B9F3BF137CE" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_B2679AEF0C551370EAB71B9F3BF1241F" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_PromissoryNotes2013Member" xlink:label="loc_wlkp_PromissoryNotes2013Member_2902E433B075C2C98F121B9F3BF19A32" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_B2679AEF0C551370EAB71B9F3BF1241F" xlink:to="loc_wlkp_PromissoryNotes2013Member_2902E433B075C2C98F121B9F3BF19A32" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_OpCoRevolverMember" xlink:label="loc_wlkp_OpCoRevolverMember_1AA3C41CC72AB97A665F1B9F3BF1F3C6" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_B2679AEF0C551370EAB71B9F3BF1241F" xlink:to="loc_wlkp_OpCoRevolverMember_1AA3C41CC72AB97A665F1B9F3BF1F3C6" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_MLPRevolverMember" xlink:label="loc_wlkp_MLPRevolverMember_3BB57620CD990B19F2B31B9F3BF156D7" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_B2679AEF0C551370EAB71B9F3BF1241F" xlink:to="loc_wlkp_MLPRevolverMember_3BB57620CD990B19F2B31B9F3BF156D7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_780AC731D190CC9BE7C31B9F3BF1055A" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_D9E7EAA1729E708481A21B9F3BF1277C" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_780AC731D190CC9BE7C31B9F3BF1055A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_EA27837D060B737D75B71B9F3BF1270C_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_780AC731D190CC9BE7C31B9F3BF1055A" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_EA27837D060B737D75B71B9F3BF1270C_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_EA27837D060B737D75B71B9F3BF1270C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_780AC731D190CC9BE7C31B9F3BF1055A" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_EA27837D060B737D75B71B9F3BF1270C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SeniorNotesMember" xlink:label="loc_us-gaap_SeniorNotesMember_0935B214C013627ADDF91B9F3BF1745F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_EA27837D060B737D75B71B9F3BF1270C" xlink:to="loc_us-gaap_SeniorNotesMember_0935B214C013627ADDF91B9F3BF1745F" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_SeniorUnsecuredRevolvingCreditFacilityMember" xlink:label="loc_wlkp_SeniorUnsecuredRevolvingCreditFacilityMember_F50BA6F04212D0FFF3D71B9F3BF1DEEF" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_EA27837D060B737D75B71B9F3BF1270C" xlink:to="loc_wlkp_SeniorUnsecuredRevolvingCreditFacilityMember_F50BA6F04212D0FFF3D71B9F3BF1DEEF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_14FFA2D5247A553001891B9F3BF1A2AB" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_D9E7EAA1729E708481A21B9F3BF1277C" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_14FFA2D5247A553001891B9F3BF1A2AB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_BAE535746162DB34F3A91B9F3BF15D8C_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_14FFA2D5247A553001891B9F3BF1A2AB" xlink:to="loc_us-gaap_RelatedPartyDomain_BAE535746162DB34F3A91B9F3BF15D8C_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_BAE535746162DB34F3A91B9F3BF15D8C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_14FFA2D5247A553001891B9F3BF1A2AB" xlink:to="loc_us-gaap_RelatedPartyDomain_BAE535746162DB34F3A91B9F3BF15D8C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnerMember" xlink:label="loc_us-gaap_LimitedPartnerMember_4BE3EC008ED70D751B1A1B9F3BF17220" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_BAE535746162DB34F3A91B9F3BF15D8C" xlink:to="loc_us-gaap_LimitedPartnerMember_4BE3EC008ED70D751B1A1B9F3BF17220" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DueToRelatedPartiesNoncurrent" xlink:label="loc_us-gaap_DueToRelatedPartiesNoncurrent_029F568C43F817B9C95F1B9F3BF24F90" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_8D22B7097164F8F960F91B9F3BF2C857" xlink:to="loc_us-gaap_DueToRelatedPartiesNoncurrent_029F568C43F817B9C95F1B9F3BF24F90" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongTermDebtFairValue" xlink:label="loc_us-gaap_LongTermDebtFairValue_E4753067B09ABA5D387E1B9F3BF28BA8" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_8D22B7097164F8F960F91B9F3BF2C857" xlink:to="loc_us-gaap_LongTermDebtFairValue_E4753067B09ABA5D387E1B9F3BF28BA8" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/FairValueMeasurementsTables" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/FinancialInstruments" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/FinancialInstrumentsDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CashAndCashEquivalentsLineItems" xlink:label="loc_us-gaap_CashAndCashEquivalentsLineItems_F1F02A53026B80D9DBCA76207BB4C158" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfCashAndCashEquivalentsTable" xlink:label="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTable_6F90C432920C4E1FA08176207BB41EE0" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_F1F02A53026B80D9DBCA76207BB4C158" xlink:to="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTable_6F90C432920C4E1FA08176207BB41EE0" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_GainLossOnInvestmentsByCategoryAxis" xlink:label="loc_us-gaap_GainLossOnInvestmentsByCategoryAxis_9AB7129EA3E31BAF015D76207BB4FFCC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTable_6F90C432920C4E1FA08176207BB41EE0" xlink:to="loc_us-gaap_GainLossOnInvestmentsByCategoryAxis_9AB7129EA3E31BAF015D76207BB4FFCC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_GainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostCategoriesOfInvestmentsDomain" xlink:label="loc_us-gaap_GainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostCategoriesOfInvestmentsDomain_A1B5150FD63FC4E8034D76207BB42F8A_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_GainLossOnInvestmentsByCategoryAxis_9AB7129EA3E31BAF015D76207BB4FFCC" xlink:to="loc_us-gaap_GainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostCategoriesOfInvestmentsDomain_A1B5150FD63FC4E8034D76207BB42F8A_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_GainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostCategoriesOfInvestmentsDomain" xlink:label="loc_us-gaap_GainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostCategoriesOfInvestmentsDomain_A1B5150FD63FC4E8034D76207BB42F8A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_GainLossOnInvestmentsByCategoryAxis_9AB7129EA3E31BAF015D76207BB4FFCC" xlink:to="loc_us-gaap_GainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostCategoriesOfInvestmentsDomain_A1B5150FD63FC4E8034D76207BB42F8A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_HeldtomaturitySecuritiesMember" xlink:label="loc_us-gaap_HeldtomaturitySecuritiesMember_CE7D214E93CACB37D6F576207BB4F612" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostCategoriesOfInvestmentsDomain_A1B5150FD63FC4E8034D76207BB42F8A" xlink:to="loc_us-gaap_HeldtomaturitySecuritiesMember_CE7D214E93CACB37D6F576207BB4F612" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashEquivalentsAtCarryingValue_2AEFF99CCF308381C7A876207BB45F6D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_F1F02A53026B80D9DBCA76207BB4C158" xlink:to="loc_us-gaap_CashEquivalentsAtCarryingValue_2AEFF99CCF308381C7A876207BB45F6D" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/Inventories" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/InventoriesDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/InventoriesTables" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/LongTermDebtPayableToWestlake" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/LongTermDebtPayableToWestlakeDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_737A9530BC92B508E3F71B9F3C6D81EA" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_D2A0608C9C46637E8A021B9F3C66E3D3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_737A9530BC92B508E3F71B9F3C6D81EA" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_D2A0608C9C46637E8A021B9F3C66E3D3" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_EF9D8FBDB0803A04EFA81B9F3C6634AC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_D2A0608C9C46637E8A021B9F3C66E3D3" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_EF9D8FBDB0803A04EFA81B9F3C6634AC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_C097C5461D97386E12B51B9F3C66F708_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_EF9D8FBDB0803A04EFA81B9F3C6634AC" xlink:to="loc_us-gaap_RelatedPartyDomain_C097C5461D97386E12B51B9F3C66F708_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_C097C5461D97386E12B51B9F3C66F708" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_EF9D8FBDB0803A04EFA81B9F3C6634AC" xlink:to="loc_us-gaap_RelatedPartyDomain_C097C5461D97386E12B51B9F3C66F708" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnerMember" xlink:label="loc_us-gaap_LimitedPartnerMember_56BA62A16719A7C0B2101B9F3C66630A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_C097C5461D97386E12B51B9F3C66F708" xlink:to="loc_us-gaap_LimitedPartnerMember_56BA62A16719A7C0B2101B9F3C66630A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_3A1C47C2EF3FEFBF26421B9F3C67316B" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_D2A0608C9C46637E8A021B9F3C66E3D3" xlink:to="loc_dei_LegalEntityAxis_3A1C47C2EF3FEFBF26421B9F3C67316B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_5F3FC5D11FC32BB852291B9F3C67F5DF_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_3A1C47C2EF3FEFBF26421B9F3C67316B" xlink:to="loc_dei_EntityDomain_5F3FC5D11FC32BB852291B9F3C67F5DF_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_5F3FC5D11FC32BB852291B9F3C67F5DF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_3A1C47C2EF3FEFBF26421B9F3C67316B" xlink:to="loc_dei_EntityDomain_5F3FC5D11FC32BB852291B9F3C67F5DF" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_OpCoRevolverMember" xlink:label="loc_wlkp_OpCoRevolverMember_9C994AF82543275AB84A1B9F3C676476" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_5F3FC5D11FC32BB852291B9F3C67F5DF" xlink:to="loc_wlkp_OpCoRevolverMember_9C994AF82543275AB84A1B9F3C676476" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_7481343B2AFA6906D4751B9F3C67B75B" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_D2A0608C9C46637E8A021B9F3C66E3D3" xlink:to="loc_us-gaap_DebtInstrumentAxis_7481343B2AFA6906D4751B9F3C67B75B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_B14E93A42DAD702286621B9F3C675E15_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_7481343B2AFA6906D4751B9F3C67B75B" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_B14E93A42DAD702286621B9F3C675E15_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_B14E93A42DAD702286621B9F3C675E15" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_7481343B2AFA6906D4751B9F3C67B75B" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_B14E93A42DAD702286621B9F3C675E15" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_PromissoryNotes2013Member" xlink:label="loc_wlkp_PromissoryNotes2013Member_8323F5A1719DDC14642C1B9F3C670785" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_B14E93A42DAD702286621B9F3C675E15" xlink:to="loc_wlkp_PromissoryNotes2013Member_8323F5A1719DDC14642C1B9F3C670785" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_OpCoRevolverMember" xlink:label="loc_wlkp_OpCoRevolverMember_849D5D7C7B19BF319ADD1B9F3C6CFE33" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_B14E93A42DAD702286621B9F3C675E15" xlink:to="loc_wlkp_OpCoRevolverMember_849D5D7C7B19BF319ADD1B9F3C6CFE33" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_MLPRevolverMember" xlink:label="loc_wlkp_MLPRevolverMember_41E9B149455893FAF2711B9F3C6C8EAB" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_B14E93A42DAD702286621B9F3C675E15" xlink:to="loc_wlkp_MLPRevolverMember_41E9B149455893FAF2711B9F3C6C8EAB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_CBA2EA4D399796108C431B9F3C6D1540" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_D2A0608C9C46637E8A021B9F3C66E3D3" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_CBA2EA4D399796108C431B9F3C6D1540" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_48A6BDD8BC213DD00C311B9F3C6DDD68_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_CBA2EA4D399796108C431B9F3C6D1540" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_48A6BDD8BC213DD00C311B9F3C6DDD68_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_48A6BDD8BC213DD00C311B9F3C6DDD68" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_CBA2EA4D399796108C431B9F3C6D1540" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_48A6BDD8BC213DD00C311B9F3C6DDD68" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SeniorNotesMember" xlink:label="loc_us-gaap_SeniorNotesMember_AE1D18C21C6A8A50BBC71B9F3C6DD511" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_48A6BDD8BC213DD00C311B9F3C6DDD68" xlink:to="loc_us-gaap_SeniorNotesMember_AE1D18C21C6A8A50BBC71B9F3C6DD511" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_SeniorUnsecuredRevolvingCreditFacilityMember" xlink:label="loc_wlkp_SeniorUnsecuredRevolvingCreditFacilityMember_4381B3AF93E1BEA32A171B9F3C6D8778" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_48A6BDD8BC213DD00C311B9F3C6DDD68" xlink:to="loc_wlkp_SeniorUnsecuredRevolvingCreditFacilityMember_4381B3AF93E1BEA32A171B9F3C6D8778" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_VariableRateAxis" xlink:label="loc_us-gaap_VariableRateAxis_9E6EC88785136AE3EBFC1B9F3C6DF445" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_D2A0608C9C46637E8A021B9F3C66E3D3" xlink:to="loc_us-gaap_VariableRateAxis_9E6EC88785136AE3EBFC1B9F3C6DF445" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="loc_us-gaap_VariableRateDomain_E329A18B5AD67F13880D1B9F3C6D2772_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_9E6EC88785136AE3EBFC1B9F3C6DF445" xlink:to="loc_us-gaap_VariableRateDomain_E329A18B5AD67F13880D1B9F3C6D2772_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="loc_us-gaap_VariableRateDomain_E329A18B5AD67F13880D1B9F3C6D2772" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_9E6EC88785136AE3EBFC1B9F3C6DF445" xlink:to="loc_us-gaap_VariableRateDomain_E329A18B5AD67F13880D1B9F3C6D2772" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PrimeRateMember" xlink:label="loc_us-gaap_PrimeRateMember_0153AD909DBF5C3543461B9F3C6DD5BA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_E329A18B5AD67F13880D1B9F3C6D2772" xlink:to="loc_us-gaap_PrimeRateMember_0153AD909DBF5C3543461B9F3C6DD5BA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember" xlink:label="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_CD5BAFA453EF1E0D10C61B9F3C6D29CF" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_E329A18B5AD67F13880D1B9F3C6D2772" xlink:to="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_CD5BAFA453EF1E0D10C61B9F3C6D29CF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DueToRelatedPartiesNoncurrent" xlink:label="loc_us-gaap_DueToRelatedPartiesNoncurrent_0899563E8619936673AA1B9F3C6DA297" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_737A9530BC92B508E3F71B9F3C6D81EA" xlink:to="loc_us-gaap_DueToRelatedPartiesNoncurrent_0899563E8619936673AA1B9F3C6DA297" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtWeightedAverageInterestRate" xlink:label="loc_us-gaap_LongtermDebtWeightedAverageInterestRate_07E054264D1E07DF50951B9F3C6D1EBD" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_737A9530BC92B508E3F71B9F3C6D81EA" xlink:to="loc_us-gaap_LongtermDebtWeightedAverageInterestRate_07E054264D1E07DF50951B9F3C6D1EBD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_04134C1CFED720A94C821B9F3C6D1E04" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_737A9530BC92B508E3F71B9F3C6D81EA" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_04134C1CFED720A94C821B9F3C6D1E04" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/LongTermDebtPayableToWestlakeTables" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/MajorCustomerAndConcentrationRisk" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/MajorCustomerAndConcentrationRiskDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskLineItems" xlink:label="loc_us-gaap_ConcentrationRiskLineItems_291DAEF822896DA5BA5376207BADEBFB" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskTable" xlink:label="loc_us-gaap_ConcentrationRiskTable_1500FEBC6AB3148604C276207BACA70E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_291DAEF822896DA5BA5376207BADEBFB" xlink:to="loc_us-gaap_ConcentrationRiskTable_1500FEBC6AB3148604C276207BACA70E" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_CEC47A7B7BFE9D7FDA4C76207BADF728" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_1500FEBC6AB3148604C276207BACA70E" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_CEC47A7B7BFE9D7FDA4C76207BADF728" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_0B3F34BB9CCC778A780D76207BAD2220_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_CEC47A7B7BFE9D7FDA4C76207BADF728" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_0B3F34BB9CCC778A780D76207BAD2220_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_0B3F34BB9CCC778A780D76207BAD2220" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_CEC47A7B7BFE9D7FDA4C76207BADF728" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_0B3F34BB9CCC778A780D76207BAD2220" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SalesRevenueNetMember" xlink:label="loc_us-gaap_SalesRevenueNetMember_E2E1C35D1A558FBF285976207BADE0DC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_0B3F34BB9CCC778A780D76207BAD2220" xlink:to="loc_us-gaap_SalesRevenueNetMember_E2E1C35D1A558FBF285976207BADE0DC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_567D7367AB4FC396544976207BADF440" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_1500FEBC6AB3148604C276207BACA70E" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_567D7367AB4FC396544976207BADF440" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_2BDC236C8C2A1316CB0B76207BADA71D_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_567D7367AB4FC396544976207BADF440" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_2BDC236C8C2A1316CB0B76207BADA71D_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_2BDC236C8C2A1316CB0B76207BADA71D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_567D7367AB4FC396544976207BADF440" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_2BDC236C8C2A1316CB0B76207BADA71D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CustomerConcentrationRiskMember" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_D7440D51CB7ABC37ADF576207BADFFCC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_2BDC236C8C2A1316CB0B76207BADA71D" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_D7440D51CB7ABC37ADF576207BADFFCC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MajorCustomersAxis" xlink:label="loc_us-gaap_MajorCustomersAxis_EE2D71B9FC3C4D4DDE0F76207BADCD97" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_1500FEBC6AB3148604C276207BACA70E" xlink:to="loc_us-gaap_MajorCustomersAxis_EE2D71B9FC3C4D4DDE0F76207BADCD97" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="loc_us-gaap_NameOfMajorCustomerDomain_7B7B1A4EAAC6ED1F93CB76207BADF030_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MajorCustomersAxis_EE2D71B9FC3C4D4DDE0F76207BADCD97" xlink:to="loc_us-gaap_NameOfMajorCustomerDomain_7B7B1A4EAAC6ED1F93CB76207BADF030_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="loc_us-gaap_NameOfMajorCustomerDomain_7B7B1A4EAAC6ED1F93CB76207BADF030" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MajorCustomersAxis_EE2D71B9FC3C4D4DDE0F76207BADCD97" xlink:to="loc_us-gaap_NameOfMajorCustomerDomain_7B7B1A4EAAC6ED1F93CB76207BADF030" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_971FD857044F10AD2D6076207BADFCEF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NameOfMajorCustomerDomain_7B7B1A4EAAC6ED1F93CB76207BADF030" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_971FD857044F10AD2D6076207BADFCEF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_467A3500A2000F48876776207BADDB31" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_1500FEBC6AB3148604C276207BACA70E" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_467A3500A2000F48876776207BADDB31" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_E46860E4592EBCEB09A376207BADB598_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_467A3500A2000F48876776207BADDB31" xlink:to="loc_us-gaap_RelatedPartyDomain_E46860E4592EBCEB09A376207BADB598_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_E46860E4592EBCEB09A376207BADB598" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_467A3500A2000F48876776207BADDB31" xlink:to="loc_us-gaap_RelatedPartyDomain_E46860E4592EBCEB09A376207BADB598" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="loc_us-gaap_AffiliatedEntityMember_FA009CCEC35BAEB8855976207BADF85F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_E46860E4592EBCEB09A376207BADB598" xlink:to="loc_us-gaap_AffiliatedEntityMember_FA009CCEC35BAEB8855976207BADF85F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_58D68F43608E8FF2C97B76207BAD39F4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_291DAEF822896DA5BA5376207BADEBFB" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_58D68F43608E8FF2C97B76207BAD39F4" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/OtherAssets" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/OtherAssetsDetails" xlink:type="extended">
    <loc xlink:href="wlkp-20160930.xsd#wlkp_OtherAssetsLineItems" xlink:label="loc_wlkp_OtherAssetsLineItems_D38E70CD03F93D30E69E1BE28E8A8EF4" xlink:type="locator" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_ScheduleOfOtherAssetsTable" xlink:label="loc_wlkp_ScheduleOfOtherAssetsTable_F5F8E3A8792BE69BDC3C1BE28E8A33DC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_wlkp_OtherAssetsLineItems_D38E70CD03F93D30E69E1BE28E8A8EF4" xlink:to="loc_wlkp_ScheduleOfOtherAssetsTable_F5F8E3A8792BE69BDC3C1BE28E8A33DC" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_9BE792A7A822241380CF1BE28E8A736A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_wlkp_ScheduleOfOtherAssetsTable_F5F8E3A8792BE69BDC3C1BE28E8A33DC" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_9BE792A7A822241380CF1BE28E8A736A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_B1CCFAEEE6857B9A8B821BE28E8A997A_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_9BE792A7A822241380CF1BE28E8A736A" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_B1CCFAEEE6857B9A8B821BE28E8A997A_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_B1CCFAEEE6857B9A8B821BE28E8A997A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_9BE792A7A822241380CF1BE28E8A736A" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_B1CCFAEEE6857B9A8B821BE28E8A997A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherAssetsMember" xlink:label="loc_us-gaap_OtherAssetsMember_98F1F42ED92F96F1E9251BE28E8A846F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_B1CCFAEEE6857B9A8B821BE28E8A997A" xlink:to="loc_us-gaap_OtherAssetsMember_98F1F42ED92F96F1E9251BE28E8A846F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_GoodwillGross" xlink:label="loc_us-gaap_GoodwillGross_ADC055D446202CBB96EB1BE28E8A6D19" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OtherAssetsLineItems_D38E70CD03F93D30E69E1BE28E8A8EF4" xlink:to="loc_us-gaap_GoodwillGross_ADC055D446202CBB96EB1BE28E8A6D19" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill_8C144509D2AA964CE03B1BE28E8A7791" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OtherAssetsLineItems_D38E70CD03F93D30E69E1BE28E8A8EF4" xlink:to="loc_us-gaap_Goodwill_8C144509D2AA964CE03B1BE28E8A7791" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_InterestRateContractGross" xlink:label="loc_wlkp_InterestRateContractGross_EAEA78F460B3E9EBB5451BE28E8AA779" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OtherAssetsLineItems_D38E70CD03F93D30E69E1BE28E8A8EF4" xlink:to="loc_wlkp_InterestRateContractGross_EAEA78F460B3E9EBB5451BE28E8AA779" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_InterestRateContractNet" xlink:label="loc_wlkp_InterestRateContractNet_0CBEE87048062BA8C71B1BE28E8A7131" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OtherAssetsLineItems_D38E70CD03F93D30E69E1BE28E8A8EF4" xlink:to="loc_wlkp_InterestRateContractNet_0CBEE87048062BA8C71B1BE28E8A7131" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_TurnaroundCostsGross" xlink:label="loc_wlkp_TurnaroundCostsGross_8ED55182ED804265DF1E1BE28E8A1C23" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OtherAssetsLineItems_D38E70CD03F93D30E69E1BE28E8A8EF4" xlink:to="loc_wlkp_TurnaroundCostsGross_8ED55182ED804265DF1E1BE28E8A1C23" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_AccumulatedAmortizationTurnaroundCosts" xlink:label="loc_wlkp_AccumulatedAmortizationTurnaroundCosts_6EAF3250C4CBC61365341BE28E8AD751" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OtherAssetsLineItems_D38E70CD03F93D30E69E1BE28E8A8EF4" xlink:to="loc_wlkp_AccumulatedAmortizationTurnaroundCosts_6EAF3250C4CBC61365341BE28E8AD751" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_TurnaroundCostsNet" xlink:label="loc_wlkp_TurnaroundCostsNet_594915A52E246F25CDDE1BE28E8A7AD8" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OtherAssetsLineItems_D38E70CD03F93D30E69E1BE28E8A8EF4" xlink:to="loc_wlkp_TurnaroundCostsNet_594915A52E246F25CDDE1BE28E8A7AD8" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_NoncurrentAssetsOtherGross" xlink:label="loc_wlkp_NoncurrentAssetsOtherGross_D74A01CC1094F32C3A261BE28E8A8D1E" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OtherAssetsLineItems_D38E70CD03F93D30E69E1BE28E8A8EF4" xlink:to="loc_wlkp_NoncurrentAssetsOtherGross_D74A01CC1094F32C3A261BE28E8A8D1E" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_AccumulatedAmortizationNoncurrentAssetsOther" xlink:label="loc_wlkp_AccumulatedAmortizationNoncurrentAssetsOther_C5E2D2D33C208C37B1991BE28E8AEE09" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OtherAssetsLineItems_D38E70CD03F93D30E69E1BE28E8A8EF4" xlink:to="loc_wlkp_AccumulatedAmortizationNoncurrentAssetsOther_C5E2D2D33C208C37B1991BE28E8AEE09" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_NoncurrentAssetsOtherNet" xlink:label="loc_wlkp_NoncurrentAssetsOtherNet_2BDAB9EFDE37EFE11D7C1BE28E8AA77B" xlink:type="locator" />
    <definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OtherAssetsLineItems_D38E70CD03F93D30E69E1BE28E8A8EF4" xlink:to="loc_wlkp_NoncurrentAssetsOtherNet_2BDAB9EFDE37EFE11D7C1BE28E8AA77B" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_TotalDeferredChargesandOtherAssetsNoncurrentGross" xlink:label="loc_wlkp_TotalDeferredChargesandOtherAssetsNoncurrentGross_218D3FA9ABA715AFECA11BE28E9408DD" xlink:type="locator" />
    <definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OtherAssetsLineItems_D38E70CD03F93D30E69E1BE28E8A8EF4" xlink:to="loc_wlkp_TotalDeferredChargesandOtherAssetsNoncurrentGross_218D3FA9ABA715AFECA11BE28E9408DD" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_AccumulatedAmortizationTotalDeferredChargesandOtherAssetsNonCurrent" xlink:label="loc_wlkp_AccumulatedAmortizationTotalDeferredChargesandOtherAssetsNonCurrent_A3F89E0C750B82D55C271BE28E94C67E" xlink:type="locator" />
    <definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OtherAssetsLineItems_D38E70CD03F93D30E69E1BE28E8A8EF4" xlink:to="loc_wlkp_AccumulatedAmortizationTotalDeferredChargesandOtherAssetsNonCurrent_A3F89E0C750B82D55C271BE28E94C67E" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_TotalDeferredChargesandOtherAssetsNonCurrentNet" xlink:label="loc_wlkp_TotalDeferredChargesandOtherAssetsNonCurrentNet_2E86F0B5454038461B8E1BE28E9472AC" xlink:type="locator" />
    <definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OtherAssetsLineItems_D38E70CD03F93D30E69E1BE28E8A8EF4" xlink:to="loc_wlkp_TotalDeferredChargesandOtherAssetsNonCurrentNet_2E86F0B5454038461B8E1BE28E9472AC" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_OtherAssetsNoncurrentAccumulatedAmortization" xlink:label="loc_wlkp_OtherAssetsNoncurrentAccumulatedAmortization_35A39DB0607C20AEFA231BE28E94B538" xlink:type="locator" />
    <definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OtherAssetsLineItems_D38E70CD03F93D30E69E1BE28E8A8EF4" xlink:to="loc_wlkp_OtherAssetsNoncurrentAccumulatedAmortization_35A39DB0607C20AEFA231BE28E94B538" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_OtherAssetsNoncurrentGross" xlink:label="loc_wlkp_OtherAssetsNoncurrentGross_3143F5811F4C1B685A3C1BE28E94946C" xlink:type="locator" />
    <definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OtherAssetsLineItems_D38E70CD03F93D30E69E1BE28E8A8EF4" xlink:to="loc_wlkp_OtherAssetsNoncurrentGross_3143F5811F4C1B685A3C1BE28E94946C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_678CED1FC8DC21EFB1561BE28E94867C" xlink:type="locator" />
    <definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OtherAssetsLineItems_D38E70CD03F93D30E69E1BE28E8A8EF4" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_678CED1FC8DC21EFB1561BE28E94867C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AdjustmentForAmortization" xlink:label="loc_us-gaap_AdjustmentForAmortization_BFD6D6B9D0CB1768194C1BE28E947898" xlink:type="locator" />
    <definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OtherAssetsLineItems_D38E70CD03F93D30E69E1BE28E8A8EF4" xlink:to="loc_us-gaap_AdjustmentForAmortization_BFD6D6B9D0CB1768194C1BE28E947898" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/OtherAssetsTables" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/PropertyPlantAndEquipment" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/PropertyPlantAndEquipmentDetail" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactions" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsAccountsReceivableFromAndAccountsPayableToRelatedPartiesDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_B148ED8F59425B6B0EBB76207BF9B381" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_15A1948A5BCA180D5DC976207BF8A116" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_B148ED8F59425B6B0EBB76207BF9B381" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_15A1948A5BCA180D5DC976207BF8A116" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_0CF6FB46F9DBC8E4A04E76207BF8CDB2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_15A1948A5BCA180D5DC976207BF8A116" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_0CF6FB46F9DBC8E4A04E76207BF8CDB2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_6E2C463E27FC494D51AF76207BF8BC1A_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_0CF6FB46F9DBC8E4A04E76207BF8CDB2" xlink:to="loc_us-gaap_RelatedPartyDomain_6E2C463E27FC494D51AF76207BF8BC1A_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_6E2C463E27FC494D51AF76207BF8BC1A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_0CF6FB46F9DBC8E4A04E76207BF8CDB2" xlink:to="loc_us-gaap_RelatedPartyDomain_6E2C463E27FC494D51AF76207BF8BC1A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="loc_us-gaap_AffiliatedEntityMember_33FECAC62B33B2239D9D76207BF8D767" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_6E2C463E27FC494D51AF76207BF8BC1A" xlink:to="loc_us-gaap_AffiliatedEntityMember_33FECAC62B33B2239D9D76207BF8D767" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_8BEED2EBE29ED7BF78BE76207BF83954" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_15A1948A5BCA180D5DC976207BF8A116" xlink:to="loc_us-gaap_CounterpartyNameAxis_8BEED2EBE29ED7BF78BE76207BF83954" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_1AA493B50B8DD07B02AE76207BF8662D_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_8BEED2EBE29ED7BF78BE76207BF83954" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_1AA493B50B8DD07B02AE76207BF8662D_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_1AA493B50B8DD07B02AE76207BF8662D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_8BEED2EBE29ED7BF78BE76207BF83954" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_1AA493B50B8DD07B02AE76207BF8662D" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_8B6FB14E6947EF968ED276207BF91B4E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_1AA493B50B8DD07B02AE76207BF8662D" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_8B6FB14E6947EF968ED276207BF91B4E" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_AccountsReceivableRelatedpartiesCurrentandNoncurrent" xlink:label="loc_wlkp_AccountsReceivableRelatedpartiesCurrentandNoncurrent_7832041052849EC26C4376207BF950AC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_B148ED8F59425B6B0EBB76207BF9B381" xlink:to="loc_wlkp_AccountsReceivableRelatedpartiesCurrentandNoncurrent_7832041052849EC26C4376207BF950AC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccountsPayableRelatedPartiesCurrent" xlink:label="loc_us-gaap_AccountsPayableRelatedPartiesCurrent_466A09B87CCB89F9431676207BF9DFA7" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_B148ED8F59425B6B0EBB76207BF9B381" xlink:to="loc_us-gaap_AccountsPayableRelatedPartiesCurrent_466A09B87CCB89F9431676207BF9DFA7" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsCostOfSalesFromRelatedPartiesDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_AF2D69F542996B5A19CC76207C2A0F0B" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_FFAD35505BA5709530FC76207C290242" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_AF2D69F542996B5A19CC76207C2A0F0B" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_FFAD35505BA5709530FC76207C290242" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_5D7EAD0C444013A3CE4176207C29CCD3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_FFAD35505BA5709530FC76207C290242" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_5D7EAD0C444013A3CE4176207C29CCD3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_7ADF6468C6CD5D423AD276207C298FFB_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_5D7EAD0C444013A3CE4176207C29CCD3" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_7ADF6468C6CD5D423AD276207C298FFB_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_7ADF6468C6CD5D423AD276207C298FFB" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_5D7EAD0C444013A3CE4176207C29CCD3" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_7ADF6468C6CD5D423AD276207C298FFB" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_FeedstockPurchasedMember" xlink:label="loc_wlkp_FeedstockPurchasedMember_E94B74F32B4637854FCE76207C29CE4F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_7ADF6468C6CD5D423AD276207C298FFB" xlink:to="loc_wlkp_FeedstockPurchasedMember_E94B74F32B4637854FCE76207C29CE4F" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_OtherServiceChargesMember" xlink:label="loc_wlkp_OtherServiceChargesMember_ACC3414E7CAAE11C893B76207C2913DB" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_7ADF6468C6CD5D423AD276207C298FFB" xlink:to="loc_wlkp_OtherServiceChargesMember_ACC3414E7CAAE11C893B76207C2913DB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2ED5A270DE2C7D2A141576207C2933BF" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_FFAD35505BA5709530FC76207C290242" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2ED5A270DE2C7D2A141576207C2933BF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_9ACDBDA151773FA2EE1076207C29FAB7_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2ED5A270DE2C7D2A141576207C2933BF" xlink:to="loc_us-gaap_RelatedPartyDomain_9ACDBDA151773FA2EE1076207C29FAB7_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_9ACDBDA151773FA2EE1076207C29FAB7" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2ED5A270DE2C7D2A141576207C2933BF" xlink:to="loc_us-gaap_RelatedPartyDomain_9ACDBDA151773FA2EE1076207C29FAB7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="loc_us-gaap_AffiliatedEntityMember_2FB5929FD2148FFB45C376207C293885" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_9ACDBDA151773FA2EE1076207C29FAB7" xlink:to="loc_us-gaap_AffiliatedEntityMember_2FB5929FD2148FFB45C376207C293885" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_9FB6CCED529AFAF52A8D76207C29FF93" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_FFAD35505BA5709530FC76207C290242" xlink:to="loc_us-gaap_CounterpartyNameAxis_9FB6CCED529AFAF52A8D76207C29FF93" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_7F9D5112684F1EA3E0E076207C290A97_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_9FB6CCED529AFAF52A8D76207C29FF93" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_7F9D5112684F1EA3E0E076207C290A97_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_7F9D5112684F1EA3E0E076207C290A97" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_9FB6CCED529AFAF52A8D76207C29FF93" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_7F9D5112684F1EA3E0E076207C290A97" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_D022371403B4EB90F9AF76207C299A6A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_7F9D5112684F1EA3E0E076207C290A97" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_D022371403B4EB90F9AF76207C299A6A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartiesAmountInCostOfSales" xlink:label="loc_us-gaap_RelatedPartiesAmountInCostOfSales_A2D53358FDDB6C6882D976207C2AB1BF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_AF2D69F542996B5A19CC76207C2A0F0B" xlink:to="loc_us-gaap_RelatedPartiesAmountInCostOfSales_A2D53358FDDB6C6882D976207C2AB1BF" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsDebtPayableToRelatedPartiesDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_B3C98F1FC3BAF423BB3C21ED742CD35C" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_39CA5AB02F45DF32030321ED742CDCC1" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_B3C98F1FC3BAF423BB3C21ED742CD35C" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_39CA5AB02F45DF32030321ED742CDCC1" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_8BAC6B84D9CC327CA70421ED742CA4CA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_39CA5AB02F45DF32030321ED742CDCC1" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_8BAC6B84D9CC327CA70421ED742CA4CA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_C8B7B27CFB5F3A24F50821ED742C87CA_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_8BAC6B84D9CC327CA70421ED742CA4CA" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_C8B7B27CFB5F3A24F50821ED742C87CA_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_C8B7B27CFB5F3A24F50821ED742C87CA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_8BAC6B84D9CC327CA70421ED742CA4CA" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_C8B7B27CFB5F3A24F50821ED742C87CA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SeniorNotesMember" xlink:label="loc_us-gaap_SeniorNotesMember_57DAE7114A405386023921ED742CD870" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_C8B7B27CFB5F3A24F50821ED742C87CA" xlink:to="loc_us-gaap_SeniorNotesMember_57DAE7114A405386023921ED742CD870" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_5548D83107C1A91F479B21ED742C64E5" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_39CA5AB02F45DF32030321ED742CDCC1" xlink:to="loc_dei_LegalEntityAxis_5548D83107C1A91F479B21ED742C64E5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_7A7CF1065DE92F65285B21ED742CC843_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_5548D83107C1A91F479B21ED742C64E5" xlink:to="loc_dei_EntityDomain_7A7CF1065DE92F65285B21ED742CC843_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_7A7CF1065DE92F65285B21ED742CC843" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_5548D83107C1A91F479B21ED742C64E5" xlink:to="loc_dei_EntityDomain_7A7CF1065DE92F65285B21ED742CC843" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_DE62E49617E20ABEDDFD21ED742CA213" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7A7CF1065DE92F65285B21ED742CC843" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_DE62E49617E20ABEDDFD21ED742CA213" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis" xlink:label="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_5FC9D952C11398A9446E21ED742C4332" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_39CA5AB02F45DF32030321ED742CDCC1" xlink:to="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_5FC9D952C11398A9446E21ED742C4332" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DistributionTypeDomain" xlink:label="loc_us-gaap_DistributionTypeDomain_74C6272930F0532EB3A421ED742C7F7D_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_5FC9D952C11398A9446E21ED742C4332" xlink:to="loc_us-gaap_DistributionTypeDomain_74C6272930F0532EB3A421ED742C7F7D_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DistributionTypeDomain" xlink:label="loc_us-gaap_DistributionTypeDomain_74C6272930F0532EB3A421ED742C7F7D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_5FC9D952C11398A9446E21ED742C4332" xlink:to="loc_us-gaap_DistributionTypeDomain_74C6272930F0532EB3A421ED742C7F7D" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_CashDistributionTrancheOneMember" xlink:label="loc_wlkp_CashDistributionTrancheOneMember_DFF751ABBC46B0D4201821ED742CB76A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionTypeDomain_74C6272930F0532EB3A421ED742C7F7D" xlink:to="loc_wlkp_CashDistributionTrancheOneMember_DFF751ABBC46B0D4201821ED742CB76A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis" xlink:label="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_99FDA69896ACCDDD0F2721ED742C15F9" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_39CA5AB02F45DF32030321ED742CDCC1" xlink:to="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_99FDA69896ACCDDD0F2721ED742C15F9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncentiveDistributionRecipientDomain" xlink:label="loc_us-gaap_IncentiveDistributionRecipientDomain_0638C25C8C0024EB43C821ED742CDC39_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_99FDA69896ACCDDD0F2721ED742C15F9" xlink:to="loc_us-gaap_IncentiveDistributionRecipientDomain_0638C25C8C0024EB43C821ED742CDC39_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncentiveDistributionRecipientDomain" xlink:label="loc_us-gaap_IncentiveDistributionRecipientDomain_0638C25C8C0024EB43C821ED742CDC39" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_99FDA69896ACCDDD0F2721ED742C15F9" xlink:to="loc_us-gaap_IncentiveDistributionRecipientDomain_0638C25C8C0024EB43C821ED742CDC39" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_IDRHoldersMember" xlink:label="loc_wlkp_IDRHoldersMember_3BF04814E1E4F31A92BE21ED742C3AE5" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncentiveDistributionRecipientDomain_0638C25C8C0024EB43C821ED742CDC39" xlink:to="loc_wlkp_IDRHoldersMember_3BF04814E1E4F31A92BE21ED742C3AE5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_D2BC853A88DB9608369821ED742C69C0" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_39CA5AB02F45DF32030321ED742CDCC1" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_D2BC853A88DB9608369821ED742C69C0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_BE805EF294A71BBBA43C21ED742C92E0_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_D2BC853A88DB9608369821ED742C69C0" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_BE805EF294A71BBBA43C21ED742C92E0_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_BE805EF294A71BBBA43C21ED742C92E0" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_D2BC853A88DB9608369821ED742C69C0" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_BE805EF294A71BBBA43C21ED742C92E0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccruedLiabilitiesMember" xlink:label="loc_us-gaap_AccruedLiabilitiesMember_DA5DD35604C96EAD830621ED742CD449" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_BE805EF294A71BBBA43C21ED742C92E0" xlink:to="loc_us-gaap_AccruedLiabilitiesMember_DA5DD35604C96EAD830621ED742CD449" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_240400236443A9FF160321ED742C8DC1" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_39CA5AB02F45DF32030321ED742CDCC1" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_240400236443A9FF160321ED742C8DC1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_1F6200EDA5CE25C6666F21ED742C6EE3_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_240400236443A9FF160321ED742C8DC1" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_1F6200EDA5CE25C6666F21ED742C6EE3_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_1F6200EDA5CE25C6666F21ED742C6EE3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_240400236443A9FF160321ED742C8DC1" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_1F6200EDA5CE25C6666F21ED742C6EE3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpenseMember" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpenseMember_7199F437EE5D7E62D4B021ED742CCA7F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_1F6200EDA5CE25C6666F21ED742C6EE3" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpenseMember_7199F437EE5D7E62D4B021ED742CCA7F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_D4C5565735F128EE668921ED742CF0AA" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_39CA5AB02F45DF32030321ED742CDCC1" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_D4C5565735F128EE668921ED742CF0AA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_21EB6D08343C950DBE8221ED742C9E40_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_D4C5565735F128EE668921ED742CF0AA" xlink:to="loc_us-gaap_RelatedPartyDomain_21EB6D08343C950DBE8221ED742C9E40_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_21EB6D08343C950DBE8221ED742C9E40" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_D4C5565735F128EE668921ED742CF0AA" xlink:to="loc_us-gaap_RelatedPartyDomain_21EB6D08343C950DBE8221ED742C9E40" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="loc_us-gaap_AffiliatedEntityMember_E6A40453F99D5F7A1F1C21ED742CAB58" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_21EB6D08343C950DBE8221ED742C9E40" xlink:to="loc_us-gaap_AffiliatedEntityMember_E6A40453F99D5F7A1F1C21ED742CAB58" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_99392E6CB84BDB5E0EBA21ED742C4EDB" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_39CA5AB02F45DF32030321ED742CDCC1" xlink:to="loc_us-gaap_CounterpartyNameAxis_99392E6CB84BDB5E0EBA21ED742C4EDB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_8C2E5202692A49C9835A21ED742C68F9_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_99392E6CB84BDB5E0EBA21ED742C4EDB" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_8C2E5202692A49C9835A21ED742C68F9_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_8C2E5202692A49C9835A21ED742C68F9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_99392E6CB84BDB5E0EBA21ED742C4EDB" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_8C2E5202692A49C9835A21ED742C68F9" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_F7B06FF8C990501DFF3821ED742CB92D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_8C2E5202692A49C9835A21ED742C68F9" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_F7B06FF8C990501DFF3821ED742CB92D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_InterestExpenseRelatedParty" xlink:label="loc_us-gaap_InterestExpenseRelatedParty_9C1B5F0DEADD7260113421ED742C85F4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_B3C98F1FC3BAF423BB3C21ED742CD35C" xlink:to="loc_us-gaap_InterestExpenseRelatedParty_9C1B5F0DEADD7260113421ED742C85F4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_InterestCostsCapitalized" xlink:label="loc_us-gaap_InterestCostsCapitalized_A2972C440A1FCBA542BB21ED742C38B8" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_B3C98F1FC3BAF423BB3C21ED742CD35C" xlink:to="loc_us-gaap_InterestCostsCapitalized_A2972C440A1FCBA542BB21ED742C38B8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_InterestPayableCurrent" xlink:label="loc_us-gaap_InterestPayableCurrent_DAA98FE94FBE0F498CFC21ED742C0A85" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_B3C98F1FC3BAF423BB3C21ED742CD35C" xlink:to="loc_us-gaap_InterestPayableCurrent_DAA98FE94FBE0F498CFC21ED742C0A85" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DueToRelatedPartiesNoncurrent" xlink:label="loc_us-gaap_DueToRelatedPartiesNoncurrent_D0F41E4F58A42BC6D04C21ED742C5180" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_B3C98F1FC3BAF423BB3C21ED742CD35C" xlink:to="loc_us-gaap_DueToRelatedPartiesNoncurrent_D0F41E4F58A42BC6D04C21ED742C5180" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_DebtInstrumentUnamortized" xlink:label="loc_wlkp_DebtInstrumentUnamortized_B3D613EBAE4F132C117221ED742CAA6B" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_B3C98F1FC3BAF423BB3C21ED742CD35C" xlink:to="loc_wlkp_DebtInstrumentUnamortized_B3D613EBAE4F132C117221ED742CAA6B" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsGeneralDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_344EAA9FF64506DA9DDB465690E99644" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_39ED1396488D5C69ED90465690E6C033" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_344EAA9FF64506DA9DDB465690E99644" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_39ED1396488D5C69ED90465690E6C033" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis" xlink:label="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_8FCE7C5159E3268C6D4F465690E799A4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_39ED1396488D5C69ED90465690E6C033" xlink:to="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_8FCE7C5159E3268C6D4F465690E799A4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DistributionTypeDomain" xlink:label="loc_us-gaap_DistributionTypeDomain_97F0A6D414D4ADFAB82E465690E787BD_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_8FCE7C5159E3268C6D4F465690E799A4" xlink:to="loc_us-gaap_DistributionTypeDomain_97F0A6D414D4ADFAB82E465690E787BD_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DistributionTypeDomain" xlink:label="loc_us-gaap_DistributionTypeDomain_97F0A6D414D4ADFAB82E465690E787BD" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_8FCE7C5159E3268C6D4F465690E799A4" xlink:to="loc_us-gaap_DistributionTypeDomain_97F0A6D414D4ADFAB82E465690E787BD" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_CashDistributionTrancheOneMember" xlink:label="loc_wlkp_CashDistributionTrancheOneMember_59A3FDA628B1FC090E3B465690E78A5B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionTypeDomain_97F0A6D414D4ADFAB82E465690E787BD" xlink:to="loc_wlkp_CashDistributionTrancheOneMember_59A3FDA628B1FC090E3B465690E78A5B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis" xlink:label="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_B5D088751562B9ABF927465690E72710" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_39ED1396488D5C69ED90465690E6C033" xlink:to="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_B5D088751562B9ABF927465690E72710" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncentiveDistributionRecipientDomain" xlink:label="loc_us-gaap_IncentiveDistributionRecipientDomain_E20660FDF180544E397E465690E70C58_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_B5D088751562B9ABF927465690E72710" xlink:to="loc_us-gaap_IncentiveDistributionRecipientDomain_E20660FDF180544E397E465690E70C58_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncentiveDistributionRecipientDomain" xlink:label="loc_us-gaap_IncentiveDistributionRecipientDomain_E20660FDF180544E397E465690E70C58" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_B5D088751562B9ABF927465690E72710" xlink:to="loc_us-gaap_IncentiveDistributionRecipientDomain_E20660FDF180544E397E465690E70C58" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_IDRHoldersMember" xlink:label="loc_wlkp_IDRHoldersMember_F229905F154769B0C3D6465690E73963" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncentiveDistributionRecipientDomain_E20660FDF180544E397E465690E70C58" xlink:to="loc_wlkp_IDRHoldersMember_F229905F154769B0C3D6465690E73963" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_2A718DCAE34983AEB0FD465690E7F4A8" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_39ED1396488D5C69ED90465690E6C033" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_2A718DCAE34983AEB0FD465690E7F4A8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_5392ED0F5B12BC986CD5465690E76546_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_2A718DCAE34983AEB0FD465690E7F4A8" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_5392ED0F5B12BC986CD5465690E76546_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_5392ED0F5B12BC986CD5465690E76546" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_2A718DCAE34983AEB0FD465690E7F4A8" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_5392ED0F5B12BC986CD5465690E76546" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_SiteLeaseAgreementMember" xlink:label="loc_wlkp_SiteLeaseAgreementMember_A4729030F3FEBBE16CCD465690E743D0" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_5392ED0F5B12BC986CD5465690E76546" xlink:to="loc_wlkp_SiteLeaseAgreementMember_A4729030F3FEBBE16CCD465690E743D0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_3D8D898D3D6645321CAE465690E8B8E3" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_39ED1396488D5C69ED90465690E6C033" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_3D8D898D3D6645321CAE465690E8B8E3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_F271892AC97EED2C9BD1465690E896DC_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_3D8D898D3D6645321CAE465690E8B8E3" xlink:to="loc_us-gaap_RelatedPartyDomain_F271892AC97EED2C9BD1465690E896DC_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_F271892AC97EED2C9BD1465690E896DC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_3D8D898D3D6645321CAE465690E8B8E3" xlink:to="loc_us-gaap_RelatedPartyDomain_F271892AC97EED2C9BD1465690E896DC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="loc_us-gaap_AffiliatedEntityMember_25069D2275DB78897B9C465690E8D325" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_F271892AC97EED2C9BD1465690E896DC" xlink:to="loc_us-gaap_AffiliatedEntityMember_25069D2275DB78897B9C465690E8D325" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_4A6C7F96FB29DC647711465690E8DE82" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_39ED1396488D5C69ED90465690E6C033" xlink:to="loc_us-gaap_CounterpartyNameAxis_4A6C7F96FB29DC647711465690E8DE82" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_D22D0DC73DD2F27E78AF465690E8FA43_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_4A6C7F96FB29DC647711465690E8DE82" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_D22D0DC73DD2F27E78AF465690E8FA43_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_D22D0DC73DD2F27E78AF465690E8FA43" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_4A6C7F96FB29DC647711465690E8DE82" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_D22D0DC73DD2F27E78AF465690E8FA43" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_DCDA4E5A8F69BE7545D8465690E89F42" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_D22D0DC73DD2F27E78AF465690E8FA43" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_DCDA4E5A8F69BE7545D8465690E89F42" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_771DF4B0141D2663CA47465690E82122" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_39ED1396488D5C69ED90465690E6C033" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_771DF4B0141D2663CA47465690E82122" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_43FBC3EC5E36977C7C68465690E80ECB_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_771DF4B0141D2663CA47465690E82122" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_43FBC3EC5E36977C7C68465690E80ECB_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_43FBC3EC5E36977C7C68465690E80ECB" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_771DF4B0141D2663CA47465690E82122" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_43FBC3EC5E36977C7C68465690E80ECB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SeniorNotesMember" xlink:label="loc_us-gaap_SeniorNotesMember_52CFF2290A2E586938AA465690E86D6A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_43FBC3EC5E36977C7C68465690E80ECB" xlink:to="loc_us-gaap_SeniorNotesMember_52CFF2290A2E586938AA465690E86D6A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="loc_us-gaap_CreditFacilityAxis_7269082555467E3EC5B1465690E8C942" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_39ED1396488D5C69ED90465690E6C033" xlink:to="loc_us-gaap_CreditFacilityAxis_7269082555467E3EC5B1465690E8C942" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_0C62FC6B36B919B0D80A465690E8D6B2_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_7269082555467E3EC5B1465690E8C942" xlink:to="loc_us-gaap_CreditFacilityDomain_0C62FC6B36B919B0D80A465690E8D6B2_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_0C62FC6B36B919B0D80A465690E8D6B2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_7269082555467E3EC5B1465690E8C942" xlink:to="loc_us-gaap_CreditFacilityDomain_0C62FC6B36B919B0D80A465690E8D6B2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_8598FB6A81FD8FD14733465690E83546" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_0C62FC6B36B919B0D80A465690E8D6B2" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_8598FB6A81FD8FD14733465690E83546" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_BB6584427B2234299FC0465690E9B4DA" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_39ED1396488D5C69ED90465690E6C033" xlink:to="loc_dei_LegalEntityAxis_BB6584427B2234299FC0465690E9B4DA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_D3DEC0595EC5E5650806465690E904D2_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_BB6584427B2234299FC0465690E9B4DA" xlink:to="loc_dei_EntityDomain_D3DEC0595EC5E5650806465690E904D2_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_D3DEC0595EC5E5650806465690E904D2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_BB6584427B2234299FC0465690E9B4DA" xlink:to="loc_dei_EntityDomain_D3DEC0595EC5E5650806465690E904D2" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_WestlakeChemicalOpCoLPMember" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_1A09E9DE99E88ADE8570465690E9ACCA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_D3DEC0595EC5E5650806465690E904D2" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_1A09E9DE99E88ADE8570465690E9ACCA" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_332B5113661FC48E8800465690E9163C" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_D3DEC0595EC5E5650806465690E904D2" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_332B5113661FC48E8800465690E9163C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_F16ABDC31B1F9A3BAA62465690E900E1" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_344EAA9FF64506DA9DDB465690E99644" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_F16ABDC31B1F9A3BAA62465690E900E1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongTermDebt" xlink:label="loc_us-gaap_LongTermDebt_BDB56BB2BCB07F0B4597465B62F4F243" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_344EAA9FF64506DA9DDB465690E99644" xlink:to="loc_us-gaap_LongTermDebt_BDB56BB2BCB07F0B4597465B62F4F243" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_DebtInstrumentUnamortized" xlink:label="loc_wlkp_DebtInstrumentUnamortized_3621A3F5BB9FB2A56AAB465690E9C258" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_344EAA9FF64506DA9DDB465690E99644" xlink:to="loc_wlkp_DebtInstrumentUnamortized_3621A3F5BB9FB2A56AAB465690E9C258" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsGoodsAndServicesFromRelatedPartiesThatHaveBeenCapitalizedDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_B46A1EC8CFB69511725076207C4E1657" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_3826487E14A1E5C70F4F76207C4D4C0B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_B46A1EC8CFB69511725076207C4E1657" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_3826487E14A1E5C70F4F76207C4D4C0B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_0833B90DB26DCCD21D2E76207C4D1EA1" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_3826487E14A1E5C70F4F76207C4D4C0B" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_0833B90DB26DCCD21D2E76207C4D1EA1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_8716D76EBBAD4F93BDCA76207C4D1647_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_0833B90DB26DCCD21D2E76207C4D1EA1" xlink:to="loc_us-gaap_RelatedPartyDomain_8716D76EBBAD4F93BDCA76207C4D1647_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_8716D76EBBAD4F93BDCA76207C4D1647" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_0833B90DB26DCCD21D2E76207C4D1EA1" xlink:to="loc_us-gaap_RelatedPartyDomain_8716D76EBBAD4F93BDCA76207C4D1647" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="loc_us-gaap_AffiliatedEntityMember_4D2BEE1EB12F42455AEB76207C4D7B3C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_8716D76EBBAD4F93BDCA76207C4D1647" xlink:to="loc_us-gaap_AffiliatedEntityMember_4D2BEE1EB12F42455AEB76207C4D7B3C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_94FB37294F331951E8CF76207C4D9871" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_3826487E14A1E5C70F4F76207C4D4C0B" xlink:to="loc_us-gaap_CounterpartyNameAxis_94FB37294F331951E8CF76207C4D9871" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_7BBF68E526DDA4D500A676207C4DFC97_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_94FB37294F331951E8CF76207C4D9871" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_7BBF68E526DDA4D500A676207C4DFC97_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_7BBF68E526DDA4D500A676207C4DFC97" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_94FB37294F331951E8CF76207C4D9871" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_7BBF68E526DDA4D500A676207C4DFC97" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_6DAB705D2E242ECFA72076207C4DABF7" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_7BBF68E526DDA4D500A676207C4DFC97" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_6DAB705D2E242ECFA72076207C4DABF7" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_RelatedPartyTransactionPurchasesFromRelatedPartyCapitalizedAsAssets" xlink:label="loc_wlkp_RelatedPartyTransactionPurchasesFromRelatedPartyCapitalizedAsAssets_60DC8E2152D5C5E9480D76207C4ED53C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_B46A1EC8CFB69511725076207C4E1657" xlink:to="loc_wlkp_RelatedPartyTransactionPurchasesFromRelatedPartyCapitalizedAsAssets_60DC8E2152D5C5E9480D76207C4ED53C" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsSalesToRelatedPartiesDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_5A49D1D9C1D88C604A6776207C421741" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_4FDB9127611B3250924476207C425771" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_5A49D1D9C1D88C604A6776207C421741" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_4FDB9127611B3250924476207C425771" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_DEFC802846C608EBDB9E76207C42E1E2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_4FDB9127611B3250924476207C425771" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_DEFC802846C608EBDB9E76207C42E1E2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_79B4381A96ED7F9D24E976207C4237B1_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_DEFC802846C608EBDB9E76207C42E1E2" xlink:to="loc_us-gaap_RelatedPartyDomain_79B4381A96ED7F9D24E976207C4237B1_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_79B4381A96ED7F9D24E976207C4237B1" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_DEFC802846C608EBDB9E76207C42E1E2" xlink:to="loc_us-gaap_RelatedPartyDomain_79B4381A96ED7F9D24E976207C4237B1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="loc_us-gaap_AffiliatedEntityMember_9D9BDDAF81A403237A2276207C42401A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_79B4381A96ED7F9D24E976207C4237B1" xlink:to="loc_us-gaap_AffiliatedEntityMember_9D9BDDAF81A403237A2276207C42401A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_9B029E8B7D92C516D33776207C429785" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_4FDB9127611B3250924476207C425771" xlink:to="loc_us-gaap_CounterpartyNameAxis_9B029E8B7D92C516D33776207C429785" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_24015013B2FDD31AF34D76207C425126_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_9B029E8B7D92C516D33776207C429785" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_24015013B2FDD31AF34D76207C425126_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_24015013B2FDD31AF34D76207C425126" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_9B029E8B7D92C516D33776207C429785" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_24015013B2FDD31AF34D76207C425126" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_9B0D98743AFFA4F0091976207C4280D0" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_24015013B2FDD31AF34D76207C425126" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_9B0D98743AFFA4F0091976207C4280D0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RevenueFromRelatedParties" xlink:label="loc_us-gaap_RevenueFromRelatedParties_9353DE2E37CC3184835076207C427B54" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_5A49D1D9C1D88C604A6776207C421741" xlink:to="loc_us-gaap_RevenueFromRelatedParties_9353DE2E37CC3184835076207C427B54" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsServicesFromRelatedPartiesIncludedInSgaExpensesDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_1F54C54662159379C33376207C473479" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_F31322637724F6FCBCF476207C47AF6C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_1F54C54662159379C33376207C473479" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_F31322637724F6FCBCF476207C47AF6C" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_757C3A0C555CD020BDBA76207C477560" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_F31322637724F6FCBCF476207C47AF6C" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_757C3A0C555CD020BDBA76207C477560" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_3961DBC8B7BE4411AAC576207C47512E_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_757C3A0C555CD020BDBA76207C477560" xlink:to="loc_us-gaap_RelatedPartyDomain_3961DBC8B7BE4411AAC576207C47512E_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_3961DBC8B7BE4411AAC576207C47512E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_757C3A0C555CD020BDBA76207C477560" xlink:to="loc_us-gaap_RelatedPartyDomain_3961DBC8B7BE4411AAC576207C47512E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="loc_us-gaap_AffiliatedEntityMember_71353ECFE15856ADF02E76207C4729ED" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_3961DBC8B7BE4411AAC576207C47512E" xlink:to="loc_us-gaap_AffiliatedEntityMember_71353ECFE15856ADF02E76207C4729ED" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_7E6D9F181AE7A694225576207C4750F9" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_F31322637724F6FCBCF476207C47AF6C" xlink:to="loc_us-gaap_CounterpartyNameAxis_7E6D9F181AE7A694225576207C4750F9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_8286A947CA9E789D57ED76207C47A5AF_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_7E6D9F181AE7A694225576207C4750F9" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_8286A947CA9E789D57ED76207C47A5AF_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_8286A947CA9E789D57ED76207C47A5AF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_7E6D9F181AE7A694225576207C4750F9" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_8286A947CA9E789D57ED76207C47A5AF" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_086692B34CD38C03C9B776207C473020" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_8286A947CA9E789D57ED76207C47A5AF" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_086692B34CD38C03C9B776207C473020" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionSellingGeneralAndAdministrativeExpensesFromTransactionsWithRelatedParty" xlink:label="loc_us-gaap_RelatedPartyTransactionSellingGeneralAndAdministrativeExpensesFromTransactionsWithRelatedParty_FADC23BE2D7820E04DBE76207C471018" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_1F54C54662159379C33376207C473479" xlink:to="loc_us-gaap_RelatedPartyTransactionSellingGeneralAndAdministrativeExpensesFromTransactionsWithRelatedParty_FADC23BE2D7820E04DBE76207C471018" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsSiteLeaseAgreementsDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_CD6669F9B0B242DEA28176207C58D9A4" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_115F45E73728EFE2FD5076207C57E6DC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_CD6669F9B0B242DEA28176207C58D9A4" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_115F45E73728EFE2FD5076207C57E6DC" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_78B3045DF6622F5944BC76207C571C71" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_115F45E73728EFE2FD5076207C57E6DC" xlink:to="loc_dei_LegalEntityAxis_78B3045DF6622F5944BC76207C571C71" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_FE5AF963030BFAE8C1D076207C5758F3_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_78B3045DF6622F5944BC76207C571C71" xlink:to="loc_dei_EntityDomain_FE5AF963030BFAE8C1D076207C5758F3_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_FE5AF963030BFAE8C1D076207C5758F3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_78B3045DF6622F5944BC76207C571C71" xlink:to="loc_dei_EntityDomain_FE5AF963030BFAE8C1D076207C5758F3" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_WestlakeChemicalOpCoLPMember" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_FDA9FE1C4738C9742AA776207C57E071" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_FE5AF963030BFAE8C1D076207C5758F3" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_FDA9FE1C4738C9742AA776207C57E071" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_3D501A6D263701B1BF5176207C57006D" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_115F45E73728EFE2FD5076207C57E6DC" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_3D501A6D263701B1BF5176207C57006D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_2DBC524D2887B65E5F4F76207C5715C1_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_3D501A6D263701B1BF5176207C57006D" xlink:to="loc_us-gaap_RelatedPartyDomain_2DBC524D2887B65E5F4F76207C5715C1_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_2DBC524D2887B65E5F4F76207C5715C1" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_3D501A6D263701B1BF5176207C57006D" xlink:to="loc_us-gaap_RelatedPartyDomain_2DBC524D2887B65E5F4F76207C5715C1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="loc_us-gaap_AffiliatedEntityMember_57D6175CEAC3F7CEFE7976207C574A51" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_2DBC524D2887B65E5F4F76207C5715C1" xlink:to="loc_us-gaap_AffiliatedEntityMember_57D6175CEAC3F7CEFE7976207C574A51" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_787437BF0346293E86B676207C58C4EF" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_115F45E73728EFE2FD5076207C57E6DC" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_787437BF0346293E86B676207C58C4EF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_774AF3E24BFB1806B45C76207C58910A_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_787437BF0346293E86B676207C58C4EF" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_774AF3E24BFB1806B45C76207C58910A_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_774AF3E24BFB1806B45C76207C58910A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_787437BF0346293E86B676207C58C4EF" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_774AF3E24BFB1806B45C76207C58910A" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_SiteLeaseAgreementMember" xlink:label="loc_wlkp_SiteLeaseAgreementMember_DD03613D671AB1B8751C76207C581BD9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_774AF3E24BFB1806B45C76207C58910A" xlink:to="loc_wlkp_SiteLeaseAgreementMember_DD03613D671AB1B8751C76207C581BD9" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_LesseeLeasingArrangementsOperatingLeasesNumber" xlink:label="loc_wlkp_LesseeLeasingArrangementsOperatingLeasesNumber_FDA0394CD93357DCB1B176207C58A124" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_CD6669F9B0B242DEA28176207C58D9A4" xlink:to="loc_wlkp_LesseeLeasingArrangementsOperatingLeasesNumber_FDA0394CD93357DCB1B176207C58A124" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LesseeLeasingArrangementsOperatingLeasesTermOfContract" xlink:label="loc_us-gaap_LesseeLeasingArrangementsOperatingLeasesTermOfContract_801E8EDE396B78EF66B076207C5848A3" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_CD6669F9B0B242DEA28176207C58D9A4" xlink:to="loc_us-gaap_LesseeLeasingArrangementsOperatingLeasesTermOfContract_801E8EDE396B78EF66B076207C5848A3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LeaseAndRentalExpense" xlink:label="loc_us-gaap_LeaseAndRentalExpense_6B53D5EEA1CF15FEEDB376207C580B4C" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_CD6669F9B0B242DEA28176207C58D9A4" xlink:to="loc_us-gaap_LeaseAndRentalExpense_6B53D5EEA1CF15FEEDB376207C580B4C" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsTables" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/SubsequentEvents" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/SubsequentEventsDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SubsequentEventLineItems" xlink:label="loc_us-gaap_SubsequentEventLineItems_4DC5EC56B4E19CBC3E9D1B9F3BD744F0" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SubsequentEventTable" xlink:label="loc_us-gaap_SubsequentEventTable_2740CFC65E759E1134631B9F3BD62041" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_4DC5EC56B4E19CBC3E9D1B9F3BD744F0" xlink:to="loc_us-gaap_SubsequentEventTable_2740CFC65E759E1134631B9F3BD62041" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis" xlink:label="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_96A9AC4233BAD7B665651B9F3BD61393" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_2740CFC65E759E1134631B9F3BD62041" xlink:to="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_96A9AC4233BAD7B665651B9F3BD61393" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DistributionTypeDomain" xlink:label="loc_us-gaap_DistributionTypeDomain_28977E01314E8122186E1B9F3BD63627_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_96A9AC4233BAD7B665651B9F3BD61393" xlink:to="loc_us-gaap_DistributionTypeDomain_28977E01314E8122186E1B9F3BD63627_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DistributionTypeDomain" xlink:label="loc_us-gaap_DistributionTypeDomain_28977E01314E8122186E1B9F3BD63627" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_96A9AC4233BAD7B665651B9F3BD61393" xlink:to="loc_us-gaap_DistributionTypeDomain_28977E01314E8122186E1B9F3BD63627" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CashDistributionMember" xlink:label="loc_us-gaap_CashDistributionMember_C75042E2449C7101451E1B9F3BD6A5C9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionTypeDomain_28977E01314E8122186E1B9F3BD63627" xlink:to="loc_us-gaap_CashDistributionMember_C75042E2449C7101451E1B9F3BD6A5C9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_2414E588983BC19E60941B9F3BD7EC0D" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_2740CFC65E759E1134631B9F3BD62041" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_2414E588983BC19E60941B9F3BD7EC0D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_F26B01C66BBF9ABE308C1B9F3BD74888_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_2414E588983BC19E60941B9F3BD7EC0D" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_F26B01C66BBF9ABE308C1B9F3BD74888_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_F26B01C66BBF9ABE308C1B9F3BD74888" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_2414E588983BC19E60941B9F3BD7EC0D" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_F26B01C66BBF9ABE308C1B9F3BD74888" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_CommonAndSubordinatedUnitsMember" xlink:label="loc_wlkp_CommonAndSubordinatedUnitsMember_A516EF3D0B0A370C3A631B9F3BD705FA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_F26B01C66BBF9ABE308C1B9F3BD74888" xlink:to="loc_wlkp_CommonAndSubordinatedUnitsMember_A516EF3D0B0A370C3A631B9F3BD705FA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis" xlink:label="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_25FB9B1BCD40947B64241B9F3BD7C511" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_2740CFC65E759E1134631B9F3BD62041" xlink:to="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_25FB9B1BCD40947B64241B9F3BD7C511" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncentiveDistributionRecipientDomain" xlink:label="loc_us-gaap_IncentiveDistributionRecipientDomain_EA63AFC94D070DDA41E81B9F3BD77C82_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_25FB9B1BCD40947B64241B9F3BD7C511" xlink:to="loc_us-gaap_IncentiveDistributionRecipientDomain_EA63AFC94D070DDA41E81B9F3BD77C82_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncentiveDistributionRecipientDomain" xlink:label="loc_us-gaap_IncentiveDistributionRecipientDomain_EA63AFC94D070DDA41E81B9F3BD77C82" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_25FB9B1BCD40947B64241B9F3BD7C511" xlink:to="loc_us-gaap_IncentiveDistributionRecipientDomain_EA63AFC94D070DDA41E81B9F3BD77C82" xlink:type="arc" />
    <loc xlink:href="wlkp-20160930.xsd#wlkp_IDRHoldersMember" xlink:label="loc_wlkp_IDRHoldersMember_B30707DB62A2CDDB14BD1B9F3BD7459C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncentiveDistributionRecipientDomain_EA63AFC94D070DDA41E81B9F3BD77C82" xlink:to="loc_wlkp_IDRHoldersMember_B30707DB62A2CDDB14BD1B9F3BD7459C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_21202637EEE8BEFD26E01B9F3BD7E686" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_2740CFC65E759E1134631B9F3BD62041" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_21202637EEE8BEFD26E01B9F3BD7E686" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_679E958CF27B7ED3E7931B9F3BD7F1C3_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_21202637EEE8BEFD26E01B9F3BD7E686" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_679E958CF27B7ED3E7931B9F3BD7F1C3_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_679E958CF27B7ED3E7931B9F3BD7F1C3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_21202637EEE8BEFD26E01B9F3BD7E686" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_679E958CF27B7ED3E7931B9F3BD7F1C3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaap_SubsequentEventMember_9A49851B2C158D0A8B0A1B9F3BD7D1C6" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_679E958CF27B7ED3E7931B9F3BD7F1C3" xlink:to="loc_us-gaap_SubsequentEventMember_9A49851B2C158D0A8B0A1B9F3BD7D1C6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit" xlink:label="loc_us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit_84D937B4C91A931686331B9F3BD79707" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_4DC5EC56B4E19CBC3E9D1B9F3BD744F0" xlink:to="loc_us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit_84D937B4C91A931686331B9F3BD79707" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncentiveDistributionDistributionPerYear" xlink:label="loc_us-gaap_IncentiveDistributionDistributionPerYear_89272530E264770F86331B9F3BD79200" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_4DC5EC56B4E19CBC3E9D1B9F3BD744F0" xlink:to="loc_us-gaap_IncentiveDistributionDistributionPerYear_89272530E264770F86331B9F3BD79200" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/SupplementalInformation" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/SupplementalInformationDetails" xlink:type="extended" />
</linkbase>
