<?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-20150930.xsd#AccountsReceivableThirdParties" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/AccountsReceivableThirdPartiesDetails" xlink:href="wlkp-20150930.xsd#AccountsReceivableThirdPartiesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/AccountsReceivableThirdPartiesTables" xlink:href="wlkp-20150930.xsd#AccountsReceivableThirdPartiesTables" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/AccumulatedOtherComprehensiveLoss" xlink:href="wlkp-20150930.xsd#AccumulatedOtherComprehensiveLoss" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/AccumulatedOtherComprehensiveLossDetails" xlink:href="wlkp-20150930.xsd#AccumulatedOtherComprehensiveLossDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/AccumulatedOtherComprehensiveLossTables" xlink:href="wlkp-20150930.xsd#AccumulatedOtherComprehensiveLossTables" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/CombinedAndConsolidatedStatementsOfCashFlows" xlink:href="wlkp-20150930.xsd#CombinedAndConsolidatedStatementsOfCashFlows" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/CombinedAndConsolidatedStatementsOfChangesInEquity" xlink:href="wlkp-20150930.xsd#CombinedAndConsolidatedStatementsOfChangesInEquity" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/CombinedAndConsolidatedStatementsOfOperations" xlink:href="wlkp-20150930.xsd#CombinedAndConsolidatedStatementsOfOperations" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/CommitmentsAndContingencies" xlink:href="wlkp-20150930.xsd#CommitmentsAndContingencies" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/CommitmentsAndContingenciesDetails" xlink:href="wlkp-20150930.xsd#CommitmentsAndContingenciesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/ConsolidatedBalanceSheets" xlink:href="wlkp-20150930.xsd#ConsolidatedBalanceSheets" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:href="wlkp-20150930.xsd#ConsolidatedBalanceSheetsParenthetical" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/ConsolidatedStatementsOfComprehensiveIncome" xlink:href="wlkp-20150930.xsd#ConsolidatedStatementsOfComprehensiveIncome" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/DerivativeInstruments" xlink:href="wlkp-20150930.xsd#DerivativeInstruments" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/DerivativeInstrumentsDetails" xlink:href="wlkp-20150930.xsd#DerivativeInstrumentsDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/DerivativeInstrumentsIneffectivePortionDetails" xlink:href="wlkp-20150930.xsd#DerivativeInstrumentsIneffectivePortionDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/DerivativeInstrumentsTables" xlink:href="wlkp-20150930.xsd#DerivativeInstrumentsTables" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/DescriptionOfBusinessAndBasisOfPresentation" xlink:href="wlkp-20150930.xsd#DescriptionOfBusinessAndBasisOfPresentation" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/DescriptionOfBusinessAndBasisOfPresentationDetails" xlink:href="wlkp-20150930.xsd#DescriptionOfBusinessAndBasisOfPresentationDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/DescriptionOfBusinessAndBasisOfPresentationPolicies" xlink:href="wlkp-20150930.xsd#DescriptionOfBusinessAndBasisOfPresentationPolicies" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/DocumentAndEntityInformation" xlink:href="wlkp-20150930.xsd#DocumentAndEntityInformation" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/FairValueMeasurements" xlink:href="wlkp-20150930.xsd#FairValueMeasurements" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/FairValueMeasurementsSummaryOfAssetsAndLiabilitiesAccountedAtFairValueOnRecurringAndNonrecurringBasisDetails" xlink:href="wlkp-20150930.xsd#FairValueMeasurementsSummaryOfAssetsAndLiabilitiesAccountedAtFairValueOnRecurringAndNonrecurringBasisDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/FairValueMeasurementsSummaryOfCarryingAndFairValuesOfLongTermDebtDetails" xlink:href="wlkp-20150930.xsd#FairValueMeasurementsSummaryOfCarryingAndFairValuesOfLongTermDebtDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/FairValueMeasurementsTables" xlink:href="wlkp-20150930.xsd#FairValueMeasurementsTables" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/FinancialInstruments" xlink:href="wlkp-20150930.xsd#FinancialInstruments" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/FinancialInstrumentsDetails" xlink:href="wlkp-20150930.xsd#FinancialInstrumentsDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/IncomeTaxes" xlink:href="wlkp-20150930.xsd#IncomeTaxes" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/IncomeTaxesDetail" xlink:href="wlkp-20150930.xsd#IncomeTaxesDetail" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/Inventories" xlink:href="wlkp-20150930.xsd#Inventories" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/InventoriesDetails" xlink:href="wlkp-20150930.xsd#InventoriesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/InventoriesTables" xlink:href="wlkp-20150930.xsd#InventoriesTables" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/LongTermDebtPayableToWestlake" xlink:href="wlkp-20150930.xsd#LongTermDebtPayableToWestlake" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/LongTermDebtPayableToWestlakeDetails" xlink:href="wlkp-20150930.xsd#LongTermDebtPayableToWestlakeDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/LongTermDebtPayableToWestlakeTables" xlink:href="wlkp-20150930.xsd#LongTermDebtPayableToWestlakeTables" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/MajorCustomerAndConcentrationRisk" xlink:href="wlkp-20150930.xsd#MajorCustomerAndConcentrationRisk" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/MajorCustomerAndConcentrationRiskDetails" xlink:href="wlkp-20150930.xsd#MajorCustomerAndConcentrationRiskDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/NetIncomePerLimitedPartnerUnit" xlink:href="wlkp-20150930.xsd#NetIncomePerLimitedPartnerUnit" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/NetIncomePerLimitedPartnerUnitBasicAndDilutedIncomePerLimitedPartnerUnitDetails" xlink:href="wlkp-20150930.xsd#NetIncomePerLimitedPartnerUnitBasicAndDilutedIncomePerLimitedPartnerUnitDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/NetIncomePerLimitedPartnerUnitDistributionsDeclaredDetails" xlink:href="wlkp-20150930.xsd#NetIncomePerLimitedPartnerUnitDistributionsDeclaredDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/NetIncomePerLimitedPartnerUnitIncomeInExcessOfDistributionDetails" xlink:href="wlkp-20150930.xsd#NetIncomePerLimitedPartnerUnitIncomeInExcessOfDistributionDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/NetIncomePerLimitedPartnerUnitTables" xlink:href="wlkp-20150930.xsd#NetIncomePerLimitedPartnerUnitTables" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/OtherAssets" xlink:href="wlkp-20150930.xsd#OtherAssets" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/OtherAssetsDetail" xlink:href="wlkp-20150930.xsd#OtherAssetsDetail" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/PropertyPlantAndEquipment" xlink:href="wlkp-20150930.xsd#PropertyPlantAndEquipment" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/PropertyPlantAndEquipmentDetail" xlink:href="wlkp-20150930.xsd#PropertyPlantAndEquipmentDetail" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactions" xlink:href="wlkp-20150930.xsd#RelatedPartyTransactions" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsAccountsReceivableFromAndAccountsPayableToRelatedPartiesDetails" xlink:href="wlkp-20150930.xsd#RelatedPartyTransactionsAccountsReceivableFromAndAccountsPayableToRelatedPartiesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsCostOfSalesFromRelatedPartiesDetails" xlink:href="wlkp-20150930.xsd#RelatedPartyTransactionsCostOfSalesFromRelatedPartiesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsDebtPayableToRelatedPartiesDetails" xlink:href="wlkp-20150930.xsd#RelatedPartyTransactionsDebtPayableToRelatedPartiesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsGeneralDetails" xlink:href="wlkp-20150930.xsd#RelatedPartyTransactionsGeneralDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsGoodsAndServicesFromRelatedPartiesThatHaveBeenCapitalizedDetails" xlink:href="wlkp-20150930.xsd#RelatedPartyTransactionsGoodsAndServicesFromRelatedPartiesThatHaveBeenCapitalizedDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsSalesToRelatedPartiesDetails" xlink:href="wlkp-20150930.xsd#RelatedPartyTransactionsSalesToRelatedPartiesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsServicesFromRelatedPartiesIncludedInSgaExpensesDetails" xlink:href="wlkp-20150930.xsd#RelatedPartyTransactionsServicesFromRelatedPartiesIncludedInSgaExpensesDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsSiteLeaseAgreementsDetails" xlink:href="wlkp-20150930.xsd#RelatedPartyTransactionsSiteLeaseAgreementsDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsTables" xlink:href="wlkp-20150930.xsd#RelatedPartyTransactionsTables" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/SubsequentEvents" xlink:href="wlkp-20150930.xsd#SubsequentEvents" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/SubsequentEventsDetails" xlink:href="wlkp-20150930.xsd#SubsequentEventsDetails" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/SupplementalInformation" xlink:href="wlkp-20150930.xsd#SupplementalInformation" xlink:type="simple" />
  <roleRef roleURI="http://www.westlake.com/role/SupplementalInformationDetails" xlink:href="wlkp-20150930.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/AccountsReceivableThirdPartiesDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_5210C37EA41E2C4341F9AB49EED20F4A" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_19A10D0EC888CE3E3C27AB49EED2BE39" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_5210C37EA41E2C4341F9AB49EED20F4A" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_19A10D0EC888CE3E3C27AB49EED2BE39" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_EBAFD5AC289F554A4FBEAB49EED2A5C3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_19A10D0EC888CE3E3C27AB49EED2BE39" xlink:to="loc_us-gaap_StatementScenarioAxis_EBAFD5AC289F554A4FBEAB49EED2A5C3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_6AF4972CF3F819F51ECEAB49EED2D944_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_EBAFD5AC289F554A4FBEAB49EED2A5C3" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_6AF4972CF3F819F51ECEAB49EED2D944_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_6AF4972CF3F819F51ECEAB49EED2D944" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_EBAFD5AC289F554A4FBEAB49EED2A5C3" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_6AF4972CF3F819F51ECEAB49EED2D944" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AccountsReceivableGrossCurrent" xlink:label="loc_us-gaap_AccountsReceivableGrossCurrent_21A44C59412CECE7612DAB49EED2CF47" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_5210C37EA41E2C4341F9AB49EED20F4A" xlink:to="loc_us-gaap_AccountsReceivableGrossCurrent_21A44C59412CECE7612DAB49EED2CF47" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_5103952BCEAC79DCF5A8AB49EED296C2" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_5210C37EA41E2C4341F9AB49EED20F4A" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_5103952BCEAC79DCF5A8AB49EED296C2" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_TradeCustomerReceivableNetCurrent" xlink:label="loc_wlkp_TradeCustomerReceivableNetCurrent_DE33661527A950B65A0CAB4ECBBD6AF5" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_5210C37EA41E2C4341F9AB49EED20F4A" xlink:to="loc_wlkp_TradeCustomerReceivableNetCurrent_DE33661527A950B65A0CAB4ECBBD6AF5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherReceivablesNetCurrent" xlink:label="loc_us-gaap_OtherReceivablesNetCurrent_BE5B6070DA4CF55ABEDFAB49EED377E8" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_5210C37EA41E2C4341F9AB49EED20F4A" xlink:to="loc_us-gaap_OtherReceivablesNetCurrent_BE5B6070DA4CF55ABEDFAB49EED377E8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ReceivablesNetCurrent" xlink:label="loc_us-gaap_ReceivablesNetCurrent_8C2108BC1256E8AFE897AB49EED32A58" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_5210C37EA41E2C4341F9AB49EED20F4A" xlink:to="loc_us-gaap_ReceivablesNetCurrent_8C2108BC1256E8AFE897AB49EED32A58" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/AccountsReceivableThirdPartiesTables" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/AccumulatedOtherComprehensiveLoss" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/AccumulatedOtherComprehensiveLossDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/AccumulatedOtherComprehensiveLossTables" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/CombinedAndConsolidatedStatementsOfCashFlows" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_72F9E795272786FA1F5BC8EE1B8BED9C" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_E32A0BC5C644F97B2E6BC8EE1B8ACCE4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_72F9E795272786FA1F5BC8EE1B8BED9C" xlink:to="loc_us-gaap_StatementTable_E32A0BC5C644F97B2E6BC8EE1B8ACCE4" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_A6F79F7C025067A61EC8C8EE1B8A4E99" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_E32A0BC5C644F97B2E6BC8EE1B8ACCE4" xlink:to="loc_us-gaap_StatementScenarioAxis_A6F79F7C025067A61EC8C8EE1B8A4E99" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_ADABADBD0125B0C8B815C8EE1B8A08BF_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_A6F79F7C025067A61EC8C8EE1B8A4E99" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_ADABADBD0125B0C8B815C8EE1B8A08BF_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_ADABADBD0125B0C8B815C8EE1B8A08BF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_A6F79F7C025067A61EC8C8EE1B8A4E99" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_ADABADBD0125B0C8B815C8EE1B8A08BF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_D71D782AE632EE5DCBDAC8EE1B8BFEA9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_72F9E795272786FA1F5BC8EE1B8BED9C" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_D71D782AE632EE5DCBDAC8EE1B8BFEA9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_81D41F1473AF91BE94D0C8EE1B8BAC97" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_D71D782AE632EE5DCBDAC8EE1B8BFEA9" xlink:to="loc_us-gaap_ProfitLoss_81D41F1473AF91BE94D0C8EE1B8BAC97" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_94279A9612F372A7342EC8EE1B8BB0CC" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_D71D782AE632EE5DCBDAC8EE1B8BFEA9" xlink:to="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_94279A9612F372A7342EC8EE1B8BB0CC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_938CB94982B0D85413EAC8EE1B8BB454" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_94279A9612F372A7342EC8EE1B8BB0CC" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_938CB94982B0D85413EAC8EE1B8BB454" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProvisionForDoubtfulAccounts" xlink:label="loc_us-gaap_ProvisionForDoubtfulAccounts_4F31445B8C07CDBF45DDC8EE1B8B1AAB" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_94279A9612F372A7342EC8EE1B8BB0CC" xlink:to="loc_us-gaap_ProvisionForDoubtfulAccounts_4F31445B8C07CDBF45DDC8EE1B8B1AAB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_GainLossOnDispositionOfAssets" xlink:label="loc_us-gaap_GainLossOnDispositionOfAssets_1BFE31398BFF6D45B875C8EE1B8B7D7E" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_94279A9612F372A7342EC8EE1B8BB0CC" xlink:to="loc_us-gaap_GainLossOnDispositionOfAssets_1BFE31398BFF6D45B875C8EE1B8B7D7E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_E00CF10EEC9B2B30C245C8EE1B8B48C1" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_94279A9612F372A7342EC8EE1B8BB0CC" xlink:to="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_E00CF10EEC9B2B30C245C8EE1B8B48C1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions_1F53E1D3D82E284E94AFC8EE1B8B259D" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_94279A9612F372A7342EC8EE1B8BB0CC" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions_1F53E1D3D82E284E94AFC8EE1B8B259D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_CD88E6CB9F9FC916CFF5C8EE1B8BDD30" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_94279A9612F372A7342EC8EE1B8BB0CC" xlink:to="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_CD88E6CB9F9FC916CFF5C8EE1B8BDD30" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsAndOtherReceivables" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsAndOtherReceivables_14992EC687698F54DA14C8EE1B8BCD51" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_CD88E6CB9F9FC916CFF5C8EE1B8BDD30" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsAndOtherReceivables_14992EC687698F54DA14C8EE1B8BCD51" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsReceivableRelatedParties" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivableRelatedParties_76541BFC6FA08145A2EAC8EE1B8B4A45" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_CD88E6CB9F9FC916CFF5C8EE1B8BDD30" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsReceivableRelatedParties_76541BFC6FA08145A2EAC8EE1B8B4A45" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInInventories" xlink:label="loc_us-gaap_IncreaseDecreaseInInventories_F6F60C2287DA550B1412C8EE1B8BE137" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_CD88E6CB9F9FC916CFF5C8EE1B8BDD30" xlink:to="loc_us-gaap_IncreaseDecreaseInInventories_F6F60C2287DA550B1412C8EE1B8BE137" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_IncreaseDecreaseInPrepaidExpensesAndOtherCurrentAssets" xlink:label="loc_wlkp_IncreaseDecreaseInPrepaidExpensesAndOtherCurrentAssets_F855C1717AE0B1CEF860C8EE1B8B7825" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_CD88E6CB9F9FC916CFF5C8EE1B8BDD30" xlink:to="loc_wlkp_IncreaseDecreaseInPrepaidExpensesAndOtherCurrentAssets_F855C1717AE0B1CEF860C8EE1B8B7825" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayable_DB5B2467507991BF5052C8EE1B8B72B0" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_CD88E6CB9F9FC916CFF5C8EE1B8BDD30" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayable_DB5B2467507991BF5052C8EE1B8B72B0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInAccruedLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_A4F93444E0A80E5AF098C8EE1B8CF163" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_CD88E6CB9F9FC916CFF5C8EE1B8BDD30" xlink:to="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_A4F93444E0A80E5AF098C8EE1B8CF163" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_FA37AA27EFF989B80A80C8EE1B8C00B1" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_CD88E6CB9F9FC916CFF5C8EE1B8BDD30" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_FA37AA27EFF989B80A80C8EE1B8C00B1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_3E62F45D3D1C6358060BC8EE1B8CFF61" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_94279A9612F372A7342EC8EE1B8BB0CC" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_3E62F45D3D1C6358060BC8EE1B8CFF61" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_D4E08B0D62CD3B9728F7C8EE1B8CDE05" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_72F9E795272786FA1F5BC8EE1B8BED9C" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_D4E08B0D62CD3B9728F7C8EE1B8CDE05" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_EAA988CBA274A7CF0BD8C8EE1B8C2CE6" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_D4E08B0D62CD3B9728F7C8EE1B8CDE05" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_EAA988CBA274A7CF0BD8C8EE1B8C2CE6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PaymentsForProceedsFromDerivativeInstrumentInvestingActivities" xlink:label="loc_us-gaap_PaymentsForProceedsFromDerivativeInstrumentInvestingActivities_108CC62A285EDB543320C8EE1B8C45B9" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_D4E08B0D62CD3B9728F7C8EE1B8CDE05" xlink:to="loc_us-gaap_PaymentsForProceedsFromDerivativeInstrumentInvestingActivities_108CC62A285EDB543320C8EE1B8C45B9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_35150AA1F0B2992F79F3C8EE1B8C1C90" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_D4E08B0D62CD3B9728F7C8EE1B8CDE05" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_35150AA1F0B2992F79F3C8EE1B8C1C90" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D43F0DE76415D0D60C1BC8EE1B8CC856" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_72F9E795272786FA1F5BC8EE1B8BED9C" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D43F0DE76415D0D60C1BC8EE1B8CC856" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProceedsFromRelatedPartyDebt" xlink:label="loc_us-gaap_ProceedsFromRelatedPartyDebt_751778193BBC1B6E7D33C8EE1B8CE63B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D43F0DE76415D0D60C1BC8EE1B8CC856" xlink:to="loc_us-gaap_ProceedsFromRelatedPartyDebt_751778193BBC1B6E7D33C8EE1B8CE63B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepaymentsOfRelatedPartyDebt" xlink:label="loc_us-gaap_RepaymentsOfRelatedPartyDebt_7338AE67F3B15469E06FC8EE1B8CBC18" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D43F0DE76415D0D60C1BC8EE1B8CC856" xlink:to="loc_us-gaap_RepaymentsOfRelatedPartyDebt_7338AE67F3B15469E06FC8EE1B8CBC18" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_Repaymentofrelatedpartydebtwithproceedsfromtheinitialpublicoffering" xlink:label="loc_wlkp_Repaymentofrelatedpartydebtwithproceedsfromtheinitialpublicoffering_4B723A5C59BBC9F8C14BC8EE1B8C25D8" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D43F0DE76415D0D60C1BC8EE1B8CC856" xlink:to="loc_wlkp_Repaymentofrelatedpartydebtwithproceedsfromtheinitialpublicoffering_4B723A5C59BBC9F8C14BC8EE1B8C25D8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonLimitedPartnersUnits" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfCommonLimitedPartnersUnits_98A0B942400B980E117EC8EE1B8C9316" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D43F0DE76415D0D60C1BC8EE1B8CC856" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfCommonLimitedPartnersUnits_98A0B942400B980E117EC8EE1B8C9316" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PaymentsOfCapitalDistribution" xlink:label="loc_us-gaap_PaymentsOfCapitalDistribution_8DF8F3EDB2B36AA8CDDDC8EE1B8C784B" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D43F0DE76415D0D60C1BC8EE1B8CC856" xlink:to="loc_us-gaap_PaymentsOfCapitalDistribution_8DF8F3EDB2B36AA8CDDDC8EE1B8C784B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PaymentsOfDistributionsToAffiliates" xlink:label="loc_us-gaap_PaymentsOfDistributionsToAffiliates_2621F83000EC3175C447C8EE1B8CE7CE" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D43F0DE76415D0D60C1BC8EE1B8CC856" xlink:to="loc_us-gaap_PaymentsOfDistributionsToAffiliates_2621F83000EC3175C447C8EE1B8CE7CE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PaymentsToMinorityShareholders" xlink:label="loc_us-gaap_PaymentsToMinorityShareholders_40C789A95793DB926B46C8EE1B8CB95B" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D43F0DE76415D0D60C1BC8EE1B8CC856" xlink:to="loc_us-gaap_PaymentsToMinorityShareholders_40C789A95793DB926B46C8EE1B8CB95B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DistributionMadeToLimitedPartnerCashDistributionsPaid" xlink:label="loc_us-gaap_DistributionMadeToLimitedPartnerCashDistributionsPaid_E7CA588098016EDF1296C8EE1B8C8F07" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D43F0DE76415D0D60C1BC8EE1B8CC856" xlink:to="loc_us-gaap_DistributionMadeToLimitedPartnerCashDistributionsPaid_E7CA588098016EDF1296C8EE1B8C8F07" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_9FF0A1669587BBC58AC7C8EE1B8CF69B" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D43F0DE76415D0D60C1BC8EE1B8CC856" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_9FF0A1669587BBC58AC7C8EE1B8CF69B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:label="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_3EB4F0B3D57B7AE8686EC8EE1B8C59AB" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_72F9E795272786FA1F5BC8EE1B8BED9C" xlink:to="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_3EB4F0B3D57B7AE8686EC8EE1B8C59AB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_CC55F610D8BF0AB42B39C8EE1B8D94DF" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_72F9E795272786FA1F5BC8EE1B8BED9C" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_CC55F610D8BF0AB42B39C8EE1B8D94DF" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/CombinedAndConsolidatedStatementsOfChangesInEquity" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_5E6349CF7EA33F72A1DAC8EE1B94C92C" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_875C90796D76F28B6A11C8EE1B93D077" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_5E6349CF7EA33F72A1DAC8EE1B94C92C" xlink:to="loc_us-gaap_StatementTable_875C90796D76F28B6A11C8EE1B93D077" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_55B9A36EFCA0D15666E9C8EE1B93AF08" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_875C90796D76F28B6A11C8EE1B93D077" xlink:to="loc_us-gaap_StatementScenarioAxis_55B9A36EFCA0D15666E9C8EE1B93AF08" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_A8B756C604A36572EAD5C8EE1B93D55F_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_55B9A36EFCA0D15666E9C8EE1B93AF08" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_A8B756C604A36572EAD5C8EE1B93D55F_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_A8B756C604A36572EAD5C8EE1B93D55F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_55B9A36EFCA0D15666E9C8EE1B93AF08" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_A8B756C604A36572EAD5C8EE1B93D55F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PredecessorMember" xlink:label="loc_us-gaap_PredecessorMember_8CFF3C4CFB884A2AE4BEC8EE1B9382FA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScenarioUnspecifiedDomain_A8B756C604A36572EAD5C8EE1B93D55F" xlink:to="loc_us-gaap_PredecessorMember_8CFF3C4CFB884A2AE4BEC8EE1B9382FA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_47F84F2FC7DCA67C82BDC8EE1B939BF1" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_875C90796D76F28B6A11C8EE1B93D077" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_47F84F2FC7DCA67C82BDC8EE1B939BF1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_B409C950A2BB696C9B1FC8EE1B937BAD_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_47F84F2FC7DCA67C82BDC8EE1B939BF1" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_B409C950A2BB696C9B1FC8EE1B937BAD_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_B409C950A2BB696C9B1FC8EE1B937BAD" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_47F84F2FC7DCA67C82BDC8EE1B939BF1" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_B409C950A2BB696C9B1FC8EE1B937BAD" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_CommonUnitsMember" xlink:label="loc_wlkp_CommonUnitsMember_B23D7C1547183DAEA0FEC8EE1B937CA7" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_B409C950A2BB696C9B1FC8EE1B937BAD" xlink:to="loc_wlkp_CommonUnitsMember_B23D7C1547183DAEA0FEC8EE1B937CA7" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_SubordinatedUnitsMember" xlink:label="loc_wlkp_SubordinatedUnitsMember_623AF3469846751DC43BC8EE1B937335" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_B409C950A2BB696C9B1FC8EE1B937BAD" xlink:to="loc_wlkp_SubordinatedUnitsMember_623AF3469846751DC43BC8EE1B937335" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_4CB54E7A713A969718C7C8EE1B931444" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_875C90796D76F28B6A11C8EE1B93D077" xlink:to="loc_us-gaap_CounterpartyNameAxis_4CB54E7A713A969718C7C8EE1B931444" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_FDF4D91AA135550EA49CC8EE1B93B62B_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_4CB54E7A713A969718C7C8EE1B931444" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_FDF4D91AA135550EA49CC8EE1B93B62B_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_FDF4D91AA135550EA49CC8EE1B93B62B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_4CB54E7A713A969718C7C8EE1B931444" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_FDF4D91AA135550EA49CC8EE1B93B62B" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_UnidentifiedThirdPartiesMember" xlink:label="loc_wlkp_UnidentifiedThirdPartiesMember_C3AD73D5033A0B8AAC01C8EE1B93E87B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_FDF4D91AA135550EA49CC8EE1B93B62B" xlink:to="loc_wlkp_UnidentifiedThirdPartiesMember_C3AD73D5033A0B8AAC01C8EE1B93E87B" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_BFF2C3AF67EE1263EE76C8EE1B93D346" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_FDF4D91AA135550EA49CC8EE1B93B62B" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_BFF2C3AF67EE1263EE76C8EE1B93D346" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_B144045145C224EDCFEAC8EE1B935383" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_875C90796D76F28B6A11C8EE1B93D077" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_B144045145C224EDCFEAC8EE1B935383" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_731765AA6A25430A60E3C8EE1B94B8BF_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_B144045145C224EDCFEAC8EE1B935383" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_731765AA6A25430A60E3C8EE1B94B8BF_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_731765AA6A25430A60E3C8EE1B94B8BF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_B144045145C224EDCFEAC8EE1B935383" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_731765AA6A25430A60E3C8EE1B94B8BF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnerMember" xlink:label="loc_us-gaap_LimitedPartnerMember_6C3943B868DEFE78027AC8EE1B94FF6B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_731765AA6A25430A60E3C8EE1B94B8BF" xlink:to="loc_us-gaap_LimitedPartnerMember_6C3943B868DEFE78027AC8EE1B94FF6B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_GeneralPartnerMember" xlink:label="loc_us-gaap_GeneralPartnerMember_4552C12FF659915007CDC8EE1B94F8AC" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_731765AA6A25430A60E3C8EE1B94B8BF" xlink:to="loc_us-gaap_GeneralPartnerMember_4552C12FF659915007CDC8EE1B94F8AC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_81644886B4DC5BA22730C8EE1B943B06" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_875C90796D76F28B6A11C8EE1B93D077" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_81644886B4DC5BA22730C8EE1B943B06" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_0F42C3D9B79C3C24B565C8EE1B945E7A_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_81644886B4DC5BA22730C8EE1B943B06" xlink:to="loc_us-gaap_EquityComponentDomain_0F42C3D9B79C3C24B565C8EE1B945E7A_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_0F42C3D9B79C3C24B565C8EE1B945E7A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_81644886B4DC5BA22730C8EE1B943B06" xlink:to="loc_us-gaap_EquityComponentDomain_0F42C3D9B79C3C24B565C8EE1B945E7A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NoncontrollingInterestMember" xlink:label="loc_us-gaap_NoncontrollingInterestMember_49019205DC25953A8292C8EE1B94D68D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_0F42C3D9B79C3C24B565C8EE1B945E7A" xlink:to="loc_us-gaap_NoncontrollingInterestMember_49019205DC25953A8292C8EE1B94D68D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_DB8ACACA794C77033655C8EE1B9430B3" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_0F42C3D9B79C3C24B565C8EE1B945E7A" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_DB8ACACA794C77033655C8EE1B9430B3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_82248E318968B5482DEEC8EE1B9467F8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5E6349CF7EA33F72A1DAC8EE1B94C92C" xlink:to="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_82248E318968B5482DEEC8EE1B9467F8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_742D6AB21575A250A7C8C8EE1B9441DB" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5E6349CF7EA33F72A1DAC8EE1B94C92C" xlink:to="loc_us-gaap_ProfitLoss_742D6AB21575A250A7C8C8EE1B9441DB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PartnersCapitalAccountDistributions" xlink:label="loc_us-gaap_PartnersCapitalAccountDistributions_A34388C74943CF99D0A5C8EE1B943A06" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5E6349CF7EA33F72A1DAC8EE1B94C92C" xlink:to="loc_us-gaap_PartnersCapitalAccountDistributions_A34388C74943CF99D0A5C8EE1B943A06" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_PartnersCapitalPredecessorNetLiabilitiesNotAssumedBySubsidiary" xlink:label="loc_wlkp_PartnersCapitalPredecessorNetLiabilitiesNotAssumedBySubsidiary_8D5EBAAF7C73582C2DD5C8EE1B94E19E" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5E6349CF7EA33F72A1DAC8EE1B94C92C" xlink:to="loc_wlkp_PartnersCapitalPredecessorNetLiabilitiesNotAssumedBySubsidiary_8D5EBAAF7C73582C2DD5C8EE1B94E19E" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_PartnersCapitalAllocationOfNetInvestmentToUnitholders" xlink:label="loc_wlkp_PartnersCapitalAllocationOfNetInvestmentToUnitholders_1C2DE0B4B83603F6B27DC8EE1B9409D3" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5E6349CF7EA33F72A1DAC8EE1B94C92C" xlink:to="loc_wlkp_PartnersCapitalAllocationOfNetInvestmentToUnitholders_1C2DE0B4B83603F6B27DC8EE1B9409D3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PartnersCapitalAccountPublicSaleOfUnits" xlink:label="loc_us-gaap_PartnersCapitalAccountPublicSaleOfUnits_366605ED30B856D1F132C8EE1B9409DD" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5E6349CF7EA33F72A1DAC8EE1B94C92C" xlink:to="loc_us-gaap_PartnersCapitalAccountPublicSaleOfUnits_366605ED30B856D1F132C8EE1B9409DD" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_NoncontrollingInterestDecreasefromDistributionstoNoncontrollingInterestHoldersReimbursement" xlink:label="loc_wlkp_NoncontrollingInterestDecreasefromDistributionstoNoncontrollingInterestHoldersReimbursement_7FCF87B2B1F52C67194AC8EE1B945FB5" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5E6349CF7EA33F72A1DAC8EE1B94C92C" xlink:to="loc_wlkp_NoncontrollingInterestDecreasefromDistributionstoNoncontrollingInterestHoldersReimbursement_7FCF87B2B1F52C67194AC8EE1B945FB5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance" xlink:label="loc_us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance_E465799884CD92A62903C8EE1B949E85" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5E6349CF7EA33F72A1DAC8EE1B94C92C" xlink:to="loc_us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance_E465799884CD92A62903C8EE1B949E85" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax_72B0BBEB752D0CA24BBFC8EE1B9417FF" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5E6349CF7EA33F72A1DAC8EE1B94C92C" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax_72B0BBEB752D0CA24BBFC8EE1B9417FF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountDistributionAmount" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountDistributionAmount_504427B176FBAE49CB69C8EE1B9479D6" xlink:type="locator" />
    <definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5E6349CF7EA33F72A1DAC8EE1B94C92C" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountDistributionAmount_504427B176FBAE49CB69C8EE1B9479D6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders" xlink:label="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_63223C33C6E817D53700C8EE1B9432F2" xlink:type="locator" />
    <definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5E6349CF7EA33F72A1DAC8EE1B94C92C" xlink:to="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_63223C33C6E817D53700C8EE1B9432F2" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/CombinedAndConsolidatedStatementsOfOperations" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_3B98B8D7D626DD2CEB08C8EE1B9FB889" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_C6F6A8304E6DBB7CD8B5C8EE1B9EFBA0" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_3B98B8D7D626DD2CEB08C8EE1B9FB889" xlink:to="loc_us-gaap_StatementTable_C6F6A8304E6DBB7CD8B5C8EE1B9EFBA0" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_DBF786957BB699AD9652C8EE1B9E01B6" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_C6F6A8304E6DBB7CD8B5C8EE1B9EFBA0" xlink:to="loc_us-gaap_StatementScenarioAxis_DBF786957BB699AD9652C8EE1B9E01B6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_D042BFBD9B87BB76113FC8EE1B9E162D_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_DBF786957BB699AD9652C8EE1B9E01B6" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_D042BFBD9B87BB76113FC8EE1B9E162D_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_D042BFBD9B87BB76113FC8EE1B9E162D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_DBF786957BB699AD9652C8EE1B9E01B6" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_D042BFBD9B87BB76113FC8EE1B9E162D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PredecessorMember" xlink:label="loc_us-gaap_PredecessorMember_AE0E5BABAF658C6384E9C8EE1B9E2617" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScenarioUnspecifiedDomain_D042BFBD9B87BB76113FC8EE1B9E162D" xlink:to="loc_us-gaap_PredecessorMember_AE0E5BABAF658C6384E9C8EE1B9E2617" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_11CFB4F8E1FD1A8A1E0FC8EE1B9E5463" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_C6F6A8304E6DBB7CD8B5C8EE1B9EFBA0" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_11CFB4F8E1FD1A8A1E0FC8EE1B9E5463" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_C5886117C625ACC03B3BC8EE1B9E6880_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_11CFB4F8E1FD1A8A1E0FC8EE1B9E5463" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_C5886117C625ACC03B3BC8EE1B9E6880_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_C5886117C625ACC03B3BC8EE1B9E6880" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_11CFB4F8E1FD1A8A1E0FC8EE1B9E5463" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_C5886117C625ACC03B3BC8EE1B9E6880" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_CommonUnitsMember" xlink:label="loc_wlkp_CommonUnitsMember_D093F15F0E0B412E42A8C8EE1B9EBA7F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_C5886117C625ACC03B3BC8EE1B9E6880" xlink:to="loc_wlkp_CommonUnitsMember_D093F15F0E0B412E42A8C8EE1B9EBA7F" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_SubordinatedUnitsMember" xlink:label="loc_wlkp_SubordinatedUnitsMember_8F47DD5CF70F4B45EC60C8EE1B9E9161" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_C5886117C625ACC03B3BC8EE1B9E6880" xlink:to="loc_wlkp_SubordinatedUnitsMember_8F47DD5CF70F4B45EC60C8EE1B9E9161" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_1782BE44C52333C0A8C4C8EE1B9E499C" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_C6F6A8304E6DBB7CD8B5C8EE1B9EFBA0" xlink:to="loc_us-gaap_CounterpartyNameAxis_1782BE44C52333C0A8C4C8EE1B9E499C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_ACBCB0461E59107B800CC8EE1B9EB719_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_1782BE44C52333C0A8C4C8EE1B9E499C" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_ACBCB0461E59107B800CC8EE1B9EB719_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_ACBCB0461E59107B800CC8EE1B9EB719" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_1782BE44C52333C0A8C4C8EE1B9E499C" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_ACBCB0461E59107B800CC8EE1B9EB719" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_UnidentifiedThirdPartiesMember" xlink:label="loc_wlkp_UnidentifiedThirdPartiesMember_181CA95ECB8B9C4DC69FC8EE1B9FA930" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_ACBCB0461E59107B800CC8EE1B9EB719" xlink:to="loc_wlkp_UnidentifiedThirdPartiesMember_181CA95ECB8B9C4DC69FC8EE1B9FA930" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_80BB4E2E89DF5EA013FEC8EE1B9F664B" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_ACBCB0461E59107B800CC8EE1B9EB719" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_80BB4E2E89DF5EA013FEC8EE1B9F664B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RevenueFromRelatedParties" xlink:label="loc_us-gaap_RevenueFromRelatedParties_7C48B44A20177597ABD0C8EE1B9F484D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B98B8D7D626DD2CEB08C8EE1B9FB889" xlink:to="loc_us-gaap_RevenueFromRelatedParties_7C48B44A20177597ABD0C8EE1B9F484D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherSalesRevenueNet" xlink:label="loc_us-gaap_OtherSalesRevenueNet_A281D4CD6BE803F281EAC8EE1B9F1D71" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B98B8D7D626DD2CEB08C8EE1B9FB889" xlink:to="loc_us-gaap_OtherSalesRevenueNet_A281D4CD6BE803F281EAC8EE1B9F1D71" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SalesRevenueNet" xlink:label="loc_us-gaap_SalesRevenueNet_DB4DA60E40B8A72BD606C8EE1B9F4A16" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B98B8D7D626DD2CEB08C8EE1B9FB889" xlink:to="loc_us-gaap_SalesRevenueNet_DB4DA60E40B8A72BD606C8EE1B9F4A16" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CostOfGoodsSold" xlink:label="loc_us-gaap_CostOfGoodsSold_78F0FF49392CADE289B9C8EE1B9F1C9B" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B98B8D7D626DD2CEB08C8EE1B9FB889" xlink:to="loc_us-gaap_CostOfGoodsSold_78F0FF49392CADE289B9C8EE1B9F1C9B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_GrossProfit" xlink:label="loc_us-gaap_GrossProfit_B9D633AC3F23EA0FEB3BC8EE1B9F6F7A" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B98B8D7D626DD2CEB08C8EE1B9FB889" xlink:to="loc_us-gaap_GrossProfit_B9D633AC3F23EA0FEB3BC8EE1B9F6F7A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_8661DF3BAD7159296E61C8EE1B9FDE8C" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B98B8D7D626DD2CEB08C8EE1B9FB889" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_8661DF3BAD7159296E61C8EE1B9FDE8C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_D5D6F68E432DF877579EC8EE1B9FF859" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B98B8D7D626DD2CEB08C8EE1B9FB889" xlink:to="loc_us-gaap_OperatingIncomeLoss_D5D6F68E432DF877579EC8EE1B9FF859" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NonoperatingIncomeExpenseAbstract" xlink:label="loc_us-gaap_NonoperatingIncomeExpenseAbstract_C7D446EE1D252F017798C8EE1B9F2F3E" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B98B8D7D626DD2CEB08C8EE1B9FB889" xlink:to="loc_us-gaap_NonoperatingIncomeExpenseAbstract_C7D446EE1D252F017798C8EE1B9F2F3E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_InterestExpenseRelatedParty" xlink:label="loc_us-gaap_InterestExpenseRelatedParty_6DE5E3FA2C462530839DC8EE1B9FFA5A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_C7D446EE1D252F017798C8EE1B9F2F3E" xlink:to="loc_us-gaap_InterestExpenseRelatedParty_6DE5E3FA2C462530839DC8EE1B9FFA5A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_9CBDC60DF61D70FE4A44C8EE1B9FAE1E" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_C7D446EE1D252F017798C8EE1B9F2F3E" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_9CBDC60DF61D70FE4A44C8EE1B9FAE1E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_2F13492CAE69B93EF8FFC8EE1B9F98A8" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B98B8D7D626DD2CEB08C8EE1B9FB889" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_2F13492CAE69B93EF8FFC8EE1B9F98A8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_6C69FF4425DB887EA222C8EE1B9F2E4B" xlink:type="locator" />
    <definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B98B8D7D626DD2CEB08C8EE1B9FB889" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_6C69FF4425DB887EA222C8EE1B9F2E4B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_B18360CFE8927AEE9615C8EE1B9FDA5D" xlink:type="locator" />
    <definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B98B8D7D626DD2CEB08C8EE1B9FB889" xlink:to="loc_us-gaap_ProfitLoss_B18360CFE8927AEE9615C8EE1B9FDA5D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_78B5BCE45FA0078C001BC8EE1B9FD489" xlink:type="locator" />
    <definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B98B8D7D626DD2CEB08C8EE1B9FB889" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_78B5BCE45FA0078C001BC8EE1B9FD489" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_35F7E221EC48EDE929C6C8EE1BA08B55" xlink:type="locator" />
    <definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B98B8D7D626DD2CEB08C8EE1B9FB889" xlink:to="loc_us-gaap_NetIncomeLoss_35F7E221EC48EDE929C6C8EE1BA08B55" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EarningsPerShareBasicAndDilutedAbstract" xlink:label="loc_us-gaap_EarningsPerShareBasicAndDilutedAbstract_80963D8AD7AC49FAE6CFC8EE1BA05970" xlink:type="locator" />
    <definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B98B8D7D626DD2CEB08C8EE1B9FB889" xlink:to="loc_us-gaap_EarningsPerShareBasicAndDilutedAbstract_80963D8AD7AC49FAE6CFC8EE1BA05970" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EarningsPerShareBasicAndDiluted" xlink:label="loc_us-gaap_EarningsPerShareBasicAndDiluted_4AA8A24961AD9DADFF8FC8EE1BA06900" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAndDilutedAbstract_80963D8AD7AC49FAE6CFC8EE1BA05970" xlink:to="loc_us-gaap_EarningsPerShareBasicAndDiluted_4AA8A24961AD9DADFF8FC8EE1BA06900" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract" xlink:label="loc_us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract_781DABD1DD415B38B2CCC8EE1BA0AFC2" xlink:type="locator" />
    <definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B98B8D7D626DD2CEB08C8EE1B9FB889" xlink:to="loc_us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract_781DABD1DD415B38B2CCC8EE1BA0AFC2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted" xlink:label="loc_us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted_3DD385AF5D47154C84E7C8EE1BA0842E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract_781DABD1DD415B38B2CCC8EE1BA0AFC2" xlink:to="loc_us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted_3DD385AF5D47154C84E7C8EE1BA0842E" xlink:type="arc" />
  </definitionLink>
  <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/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LossContingenciesLineItems" xlink:label="loc_us-gaap_LossContingenciesLineItems_1F011E907F53D8AF001703A241F8ABBC" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LossContingenciesTable" xlink:label="loc_us-gaap_LossContingenciesTable_9A15BC5A347931E2975003A241F773D5" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_1F011E907F53D8AF001703A241F8ABBC" xlink:to="loc_us-gaap_LossContingenciesTable_9A15BC5A347931E2975003A241F773D5" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LitigationCaseAxis" xlink:label="loc_us-gaap_LitigationCaseAxis_35219D140DDF9714EDB703A241F71D63" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_9A15BC5A347931E2975003A241F773D5" xlink:to="loc_us-gaap_LitigationCaseAxis_35219D140DDF9714EDB703A241F71D63" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LitigationCaseTypeDomain" xlink:label="loc_us-gaap_LitigationCaseTypeDomain_700CB4D0134189B4466403A241F85EAD_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LitigationCaseAxis_35219D140DDF9714EDB703A241F71D63" xlink:to="loc_us-gaap_LitigationCaseTypeDomain_700CB4D0134189B4466403A241F85EAD_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LitigationCaseTypeDomain" xlink:label="loc_us-gaap_LitigationCaseTypeDomain_700CB4D0134189B4466403A241F85EAD" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LitigationCaseAxis_35219D140DDF9714EDB703A241F71D63" xlink:to="loc_us-gaap_LitigationCaseTypeDomain_700CB4D0134189B4466403A241F85EAD" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_GoodrichandPolyOneMember" xlink:label="loc_wlkp_GoodrichandPolyOneMember_8666D931F7B93B966F2D03A241F88FAC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LitigationCaseTypeDomain_700CB4D0134189B4466403A241F85EAD" xlink:to="loc_wlkp_GoodrichandPolyOneMember_8666D931F7B93B966F2D03A241F88FAC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LitigationStatusAxis" xlink:label="loc_us-gaap_LitigationStatusAxis_EAAE82B49672DE58FB1203A241F8FEB9" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_9A15BC5A347931E2975003A241F773D5" xlink:to="loc_us-gaap_LitigationStatusAxis_EAAE82B49672DE58FB1203A241F8FEB9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LitigationStatusDomain" xlink:label="loc_us-gaap_LitigationStatusDomain_0AC68E6B26C4AA219D4F03A241F8AD1C_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LitigationStatusAxis_EAAE82B49672DE58FB1203A241F8FEB9" xlink:to="loc_us-gaap_LitigationStatusDomain_0AC68E6B26C4AA219D4F03A241F8AD1C_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LitigationStatusDomain" xlink:label="loc_us-gaap_LitigationStatusDomain_0AC68E6B26C4AA219D4F03A241F8AD1C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LitigationStatusAxis_EAAE82B49672DE58FB1203A241F8FEB9" xlink:to="loc_us-gaap_LitigationStatusDomain_0AC68E6B26C4AA219D4F03A241F8AD1C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SettledLitigationMember" xlink:label="loc_us-gaap_SettledLitigationMember_6FD6B04D4714F13EB6F003A241F816C0" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LitigationStatusDomain_0AC68E6B26C4AA219D4F03A241F8AD1C" xlink:to="loc_us-gaap_SettledLitigationMember_6FD6B04D4714F13EB6F003A241F816C0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PendingLitigationMember" xlink:label="loc_us-gaap_PendingLitigationMember_A631665C495FF9D0FFE503A241F84E53" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LitigationStatusDomain_0AC68E6B26C4AA219D4F03A241F8AD1C" xlink:to="loc_us-gaap_PendingLitigationMember_A631665C495FF9D0FFE503A241F84E53" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LossContingenciesByNatureOfContingencyAxis" xlink:label="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_063400D38E88F5B7EAB103A241F8A6E2" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_9A15BC5A347931E2975003A241F773D5" xlink:to="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_063400D38E88F5B7EAB103A241F8A6E2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LossContingencyNatureDomain" xlink:label="loc_us-gaap_LossContingencyNatureDomain_A989DD05C6978558E05B03A241F86916_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_063400D38E88F5B7EAB103A241F8A6E2" xlink:to="loc_us-gaap_LossContingencyNatureDomain_A989DD05C6978558E05B03A241F86916_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LossContingencyNatureDomain" xlink:label="loc_us-gaap_LossContingencyNatureDomain_A989DD05C6978558E05B03A241F86916" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_063400D38E88F5B7EAB103A241F8A6E2" xlink:to="loc_us-gaap_LossContingencyNatureDomain_A989DD05C6978558E05B03A241F86916" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_UnfavorableRegulatoryActionMember" xlink:label="loc_us-gaap_UnfavorableRegulatoryActionMember_311B483F5491BA6B99B403A241F876F9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingencyNatureDomain_A989DD05C6978558E05B03A241F86916" xlink:to="loc_us-gaap_UnfavorableRegulatoryActionMember_311B483F5491BA6B99B403A241F876F9" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_SiteContingencyThirdPartyRecoveryPercentage" xlink:label="loc_wlkp_SiteContingencyThirdPartyRecoveryPercentage_E805874AA762CC29598203A241F8ED58" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_1F011E907F53D8AF001703A241F8ABBC" xlink:to="loc_wlkp_SiteContingencyThirdPartyRecoveryPercentage_E805874AA762CC29598203A241F8ED58" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_LossContingencyArbitrationIntervalPeriod" xlink:label="loc_wlkp_LossContingencyArbitrationIntervalPeriod_4BA858B740003CCAF2BB03A241F8A2EF" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_1F011E907F53D8AF001703A241F8ABBC" xlink:to="loc_wlkp_LossContingencyArbitrationIntervalPeriod_4BA858B740003CCAF2BB03A241F8A2EF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EnvironmentalRemediationExpense" xlink:label="loc_us-gaap_EnvironmentalRemediationExpense_54D0CB3EA6CF12C194C003A241F8C6ED" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_1F011E907F53D8AF001703A241F8ABBC" xlink:to="loc_us-gaap_EnvironmentalRemediationExpense_54D0CB3EA6CF12C194C003A241F8C6ED" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LossContingencyDamagesSoughtValue" xlink:label="loc_us-gaap_LossContingencyDamagesSoughtValue_B32BD047FC77458BCFA203A241F899D2" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_1F011E907F53D8AF001703A241F8ABBC" xlink:to="loc_us-gaap_LossContingencyDamagesSoughtValue_B32BD047FC77458BCFA203A241F899D2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LossContingencyEstimateOfPossibleLoss" xlink:label="loc_us-gaap_LossContingencyEstimateOfPossibleLoss_8597B2E652EAD9509FB903A241F874E9" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_1F011E907F53D8AF001703A241F8ABBC" xlink:to="loc_us-gaap_LossContingencyEstimateOfPossibleLoss_8597B2E652EAD9509FB903A241F874E9" 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/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_0B5025473EDD040FF720B4DE95CCCCC4" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_9A9E1150B780EA72F752B4DE95CC217B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_0B5025473EDD040FF720B4DE95CCCCC4" xlink:to="loc_us-gaap_StatementTable_9A9E1150B780EA72F752B4DE95CC217B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_11F4190E22411A102080B4DE95CCBB24" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_9A9E1150B780EA72F752B4DE95CC217B" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_11F4190E22411A102080B4DE95CCBB24" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_1CE034EAB8AB76EC97AEB4DE95CC10AB_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_11F4190E22411A102080B4DE95CCBB24" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_1CE034EAB8AB76EC97AEB4DE95CC10AB_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_1CE034EAB8AB76EC97AEB4DE95CC10AB" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_11F4190E22411A102080B4DE95CCBB24" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_1CE034EAB8AB76EC97AEB4DE95CC10AB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnerMember" xlink:label="loc_us-gaap_LimitedPartnerMember_922E5A9C3DB266534EEDB4DE95CC795B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_1CE034EAB8AB76EC97AEB4DE95CC10AB" xlink:to="loc_us-gaap_LimitedPartnerMember_922E5A9C3DB266534EEDB4DE95CC795B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_GeneralPartnerMember" xlink:label="loc_us-gaap_GeneralPartnerMember_7A64DD08919C634B17F7B4DE95CC89BC" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_1CE034EAB8AB76EC97AEB4DE95CC10AB" xlink:to="loc_us-gaap_GeneralPartnerMember_7A64DD08919C634B17F7B4DE95CC89BC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_A37A31485DB21C7DBA50B4DE95CCBC35" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_9A9E1150B780EA72F752B4DE95CC217B" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_A37A31485DB21C7DBA50B4DE95CCBC35" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_F1E8AC27093315DC30DFB4DE95CC1D0F_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_A37A31485DB21C7DBA50B4DE95CCBC35" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_F1E8AC27093315DC30DFB4DE95CC1D0F_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_F1E8AC27093315DC30DFB4DE95CC1D0F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_A37A31485DB21C7DBA50B4DE95CCBC35" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_F1E8AC27093315DC30DFB4DE95CC1D0F" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_CommonUnitsMember" xlink:label="loc_wlkp_CommonUnitsMember_116C24205366A75E9DDBB4DE95CC4207" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_F1E8AC27093315DC30DFB4DE95CC1D0F" xlink:to="loc_wlkp_CommonUnitsMember_116C24205366A75E9DDBB4DE95CC4207" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_SubordinatedUnitsMember" xlink:label="loc_wlkp_SubordinatedUnitsMember_40F088E2C97BD54FAADAB4DE95CC8032" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_F1E8AC27093315DC30DFB4DE95CC1D0F" xlink:to="loc_wlkp_SubordinatedUnitsMember_40F088E2C97BD54FAADAB4DE95CC8032" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_5E271880B87683D92879B4DE95CCC2FF" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_9A9E1150B780EA72F752B4DE95CC217B" xlink:to="loc_us-gaap_CounterpartyNameAxis_5E271880B87683D92879B4DE95CCC2FF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_80EC90D2E0C407F3B7FBB4DE95CC5C36_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_5E271880B87683D92879B4DE95CCC2FF" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_80EC90D2E0C407F3B7FBB4DE95CC5C36_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_80EC90D2E0C407F3B7FBB4DE95CC5C36" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_5E271880B87683D92879B4DE95CCC2FF" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_80EC90D2E0C407F3B7FBB4DE95CC5C36" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_UnidentifiedThirdPartiesMember" xlink:label="loc_wlkp_UnidentifiedThirdPartiesMember_34DCA779B69540F3AE33B4DE95CC21AE" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_80EC90D2E0C407F3B7FBB4DE95CC5C36" xlink:to="loc_wlkp_UnidentifiedThirdPartiesMember_34DCA779B69540F3AE33B4DE95CC21AE" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_4843B969120EA636E732B4DE95CC3962" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_80EC90D2E0C407F3B7FBB4DE95CC5C36" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_4843B969120EA636E732B4DE95CC3962" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaap_AssetsAbstract_EAC7B07040868693C76EB4DE95CC9D56" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0B5025473EDD040FF720B4DE95CCCCC4" xlink:to="loc_us-gaap_AssetsAbstract_EAC7B07040868693C76EB4DE95CC9D56" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="loc_us-gaap_AssetsCurrentAbstract_741109C1615D4601558FB4DE95CCDA1A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_EAC7B07040868693C76EB4DE95CC9D56" xlink:to="loc_us-gaap_AssetsCurrentAbstract_741109C1615D4601558FB4DE95CCDA1A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_61FAFA13E832FBC904E3B4DE95CD3F34" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_741109C1615D4601558FB4DE95CCDA1A" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_61FAFA13E832FBC904E3B4DE95CD3F34" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AccountsReceivableRelatedPartiesCurrent" xlink:label="loc_us-gaap_AccountsReceivableRelatedPartiesCurrent_A7739147D5F584C5273BB4DE95CDB86E" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_741109C1615D4601558FB4DE95CCDA1A" xlink:to="loc_us-gaap_AccountsReceivableRelatedPartiesCurrent_A7739147D5F584C5273BB4DE95CDB86E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ReceivablesNetCurrent" xlink:label="loc_us-gaap_ReceivablesNetCurrent_487FAE51DFA63300BDD9B4DE95CD44FF" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_741109C1615D4601558FB4DE95CCDA1A" xlink:to="loc_us-gaap_ReceivablesNetCurrent_487FAE51DFA63300BDD9B4DE95CD44FF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_C629ACCC6D155C55563CB4DE95CD04F2" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_741109C1615D4601558FB4DE95CCDA1A" xlink:to="loc_us-gaap_InventoryNet_C629ACCC6D155C55563CB4DE95CD04F2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_68B9A24140330199651DB4DE95CD5837" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_741109C1615D4601558FB4DE95CCDA1A" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_68B9A24140330199651DB4DE95CD5837" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent_2B74BC256F2F488AEA06B4DE95CDA5CE" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_741109C1615D4601558FB4DE95CCDA1A" xlink:to="loc_us-gaap_AssetsCurrent_2B74BC256F2F488AEA06B4DE95CDA5CE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_C91DDEEE2922E1CEE5FBB4DE95CDDE31" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_EAC7B07040868693C76EB4DE95CC9D56" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_C91DDEEE2922E1CEE5FBB4DE95CDDE31" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherAssetsAbstract" xlink:label="loc_us-gaap_OtherAssetsAbstract_1AC8F8B85DB60BE55A56B4DE95CDEF6D" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_EAC7B07040868693C76EB4DE95CC9D56" xlink:to="loc_us-gaap_OtherAssetsAbstract_1AC8F8B85DB60BE55A56B4DE95CDEF6D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill_D7DCB92848776D60E2ABB4DE95CD2892" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherAssetsAbstract_1AC8F8B85DB60BE55A56B4DE95CDEF6D" xlink:to="loc_us-gaap_Goodwill_D7DCB92848776D60E2ABB4DE95CD2892" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredCostsAndOtherAssets" xlink:label="loc_us-gaap_DeferredCostsAndOtherAssets_FA5372E3814B425F0053B4DE95CD2093" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherAssetsAbstract_1AC8F8B85DB60BE55A56B4DE95CDEF6D" xlink:to="loc_us-gaap_DeferredCostsAndOtherAssets_FA5372E3814B425F0053B4DE95CD2093" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_392CF83DB7BCEFC1D538B4DE95CD5726" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherAssetsAbstract_1AC8F8B85DB60BE55A56B4DE95CDEF6D" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_392CF83DB7BCEFC1D538B4DE95CD5726" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_F20BE808CCDD17B62658B4DE95CD3361" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_EAC7B07040868693C76EB4DE95CC9D56" xlink:to="loc_us-gaap_Assets_F20BE808CCDD17B62658B4DE95CD3361" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_4AB3AF4D7D2C1683C72DB4DE95CD3A44" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0B5025473EDD040FF720B4DE95CCCCC4" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_4AB3AF4D7D2C1683C72DB4DE95CD3A44" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_B84AD33F9DCF342A5860B4DE95CDB790" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_4AB3AF4D7D2C1683C72DB4DE95CD3A44" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_B84AD33F9DCF342A5860B4DE95CDB790" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AccountsPayableRelatedPartiesCurrent" xlink:label="loc_us-gaap_AccountsPayableRelatedPartiesCurrent_89EECBBD3ED7CDCF8E95B4DE95CD5D3C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_B84AD33F9DCF342A5860B4DE95CDB790" xlink:to="loc_us-gaap_AccountsPayableRelatedPartiesCurrent_89EECBBD3ED7CDCF8E95B4DE95CD5D3C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="loc_us-gaap_AccountsPayableCurrent_2B627C0C47EAAD8390DCB4DE95CD579E" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_B84AD33F9DCF342A5860B4DE95CDB790" xlink:to="loc_us-gaap_AccountsPayableCurrent_2B627C0C47EAAD8390DCB4DE95CD579E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_21CD1A9A7DCEA4653CA5B4DE95CD3C0B" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_B84AD33F9DCF342A5860B4DE95CDB790" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_21CD1A9A7DCEA4653CA5B4DE95CD3C0B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaap_LiabilitiesCurrent_05121F9D4F09C2023BD8B4DE95CDC331" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_B84AD33F9DCF342A5860B4DE95CDB790" xlink:to="loc_us-gaap_LiabilitiesCurrent_05121F9D4F09C2023BD8B4DE95CDC331" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DueToRelatedPartiesNoncurrent" xlink:label="loc_us-gaap_DueToRelatedPartiesNoncurrent_5D37C90194EE77D60418B4DE95CD75EB" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_4AB3AF4D7D2C1683C72DB4DE95CD3A44" xlink:to="loc_us-gaap_DueToRelatedPartiesNoncurrent_5D37C90194EE77D60418B4DE95CD75EB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredTaxLiabilitiesNoncurrent" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesNoncurrent_71240B4D4C76D777BB78B4DE95CDCC46" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_4AB3AF4D7D2C1683C72DB4DE95CD3A44" xlink:to="loc_us-gaap_DeferredTaxLiabilitiesNoncurrent_71240B4D4C76D777BB78B4DE95CDCC46" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_EE69F9C7A556FB83C30EB4DE95CE73C0" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_4AB3AF4D7D2C1683C72DB4DE95CD3A44" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_EE69F9C7A556FB83C30EB4DE95CE73C0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities_19371E97FE17E34314EBB4DE95CEC99F" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_4AB3AF4D7D2C1683C72DB4DE95CD3A44" xlink:to="loc_us-gaap_Liabilities_19371E97FE17E34314EBB4DE95CEC99F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="loc_us-gaap_CommitmentsAndContingencies_E2A535124D688D48F328B4DE95CE76D7" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_4AB3AF4D7D2C1683C72DB4DE95CD3A44" xlink:to="loc_us-gaap_CommitmentsAndContingencies_E2A535124D688D48F328B4DE95CE76D7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StockholdersEquityAbstract" xlink:label="loc_us-gaap_StockholdersEquityAbstract_E0723158AC24F6743C20B4DE95CE2599" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0B5025473EDD040FF720B4DE95CCCCC4" xlink:to="loc_us-gaap_StockholdersEquityAbstract_E0723158AC24F6743C20B4DE95CE2599" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccount" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccount_797E1054FD7C99637467B4DE95CE3A71" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_E0723158AC24F6743C20B4DE95CE2599" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccount_797E1054FD7C99637467B4DE95CE3A71" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_GeneralPartnersCapitalAccount" xlink:label="loc_us-gaap_GeneralPartnersCapitalAccount_3EF81FE87B9FA2CC6B56B4DE95CE1672" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_E0723158AC24F6743C20B4DE95CE2599" xlink:to="loc_us-gaap_GeneralPartnersCapitalAccount_3EF81FE87B9FA2CC6B56B4DE95CE1672" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_6126977A1E207F16A813B4DE95CE0F21" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_E0723158AC24F6743C20B4DE95CE2599" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_6126977A1E207F16A813B4DE95CE0F21" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PartnersCapital" xlink:label="loc_us-gaap_PartnersCapital_49FDA64311962E530285B4DE95CE2D26" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_E0723158AC24F6743C20B4DE95CE2599" xlink:to="loc_us-gaap_PartnersCapital_49FDA64311962E530285B4DE95CE2D26" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_MinorityInterestInLimitedPartnerships" xlink:label="loc_us-gaap_MinorityInterestInLimitedPartnerships_77C70DB738F0EC4B5B1BB4DE95CE477C" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_E0723158AC24F6743C20B4DE95CE2599" xlink:to="loc_us-gaap_MinorityInterestInLimitedPartnerships_77C70DB738F0EC4B5B1BB4DE95CE477C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_1FA43BCCC2883FAE297BB4DE95CE4A1B" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_E0723158AC24F6743C20B4DE95CE2599" xlink:to="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_1FA43BCCC2883FAE297BB4DE95CE4A1B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_6A20A288C29DEDBF46E9B4DE95CE9B90" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_E0723158AC24F6743C20B4DE95CE2599" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_6A20A288C29DEDBF46E9B4DE95CE9B90" 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/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_C6F89D5E1985CF01AC6103A241D4978F" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_40E2537082EDA8DAB4A903A241D44F71" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_C6F89D5E1985CF01AC6103A241D4978F" xlink:to="loc_us-gaap_StatementTable_40E2537082EDA8DAB4A903A241D44F71" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_76A9A65CF97208C6E69E03A241D4EE7D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_40E2537082EDA8DAB4A903A241D44F71" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_76A9A65CF97208C6E69E03A241D4EE7D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_2800A13E26C9248F814B03A241D42A33_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_76A9A65CF97208C6E69E03A241D4EE7D" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_2800A13E26C9248F814B03A241D42A33_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_2800A13E26C9248F814B03A241D42A33" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_76A9A65CF97208C6E69E03A241D4EE7D" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_2800A13E26C9248F814B03A241D42A33" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_CommonUnitsMember" xlink:label="loc_wlkp_CommonUnitsMember_126272ACB5F0E295F2C803A241D4DF7A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_2800A13E26C9248F814B03A241D42A33" xlink:to="loc_wlkp_CommonUnitsMember_126272ACB5F0E295F2C803A241D4DF7A" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_SubordinatedUnitsMember" xlink:label="loc_wlkp_SubordinatedUnitsMember_86864BEF864372A7677E03A241D40346" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_2800A13E26C9248F814B03A241D42A33" xlink:to="loc_wlkp_SubordinatedUnitsMember_86864BEF864372A7677E03A241D40346" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_04E41AE989394AC14F1003A241D48FFF" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_40E2537082EDA8DAB4A903A241D44F71" xlink:to="loc_us-gaap_CounterpartyNameAxis_04E41AE989394AC14F1003A241D48FFF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_D8FE2C0678748FF1B79B03A241D4792B_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_04E41AE989394AC14F1003A241D48FFF" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_D8FE2C0678748FF1B79B03A241D4792B_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_D8FE2C0678748FF1B79B03A241D4792B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_04E41AE989394AC14F1003A241D48FFF" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_D8FE2C0678748FF1B79B03A241D4792B" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_566407A63C4166ED2EB203A241D49341" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_D8FE2C0678748FF1B79B03A241D4792B" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_566407A63C4166ED2EB203A241D49341" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_UnidentifiedThirdPartiesMember" xlink:label="loc_wlkp_UnidentifiedThirdPartiesMember_DFD0128927CC8B71A64B03A241D452BE" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_D8FE2C0678748FF1B79B03A241D4792B" xlink:to="loc_wlkp_UnidentifiedThirdPartiesMember_DFD0128927CC8B71A64B03A241D452BE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountUnitsIssued" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountUnitsIssued_4C86347A50972219C0B103A241D40F21" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_C6F89D5E1985CF01AC6103A241D4978F" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountUnitsIssued_4C86347A50972219C0B103A241D40F21" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding_2D5C4E7946177630B6AF03A241D4E893" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_C6F89D5E1985CF01AC6103A241D4978F" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding_2D5C4E7946177630B6AF03A241D4E893" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/ConsolidatedStatementsOfComprehensiveIncome" xlink:type="extended" />
  <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/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DerivativeLineItems" xlink:label="loc_us-gaap_DerivativeLineItems_9B5387DCB159C60EAE11C8EE1ADC48DA" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DerivativeTable" xlink:label="loc_us-gaap_DerivativeTable_B95E4FA27E50B0273D2CC8EE1ADA0CA2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_9B5387DCB159C60EAE11C8EE1ADC48DA" xlink:to="loc_us-gaap_DerivativeTable_B95E4FA27E50B0273D2CC8EE1ADA0CA2" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_33CCA862C07B28738CE1C8EE1ADBC756" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_B95E4FA27E50B0273D2CC8EE1ADA0CA2" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_33CCA862C07B28738CE1C8EE1ADBC756" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_DC92F86EAAEAB32F769FC8EE1ADB0D3D_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_33CCA862C07B28738CE1C8EE1ADBC756" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_DC92F86EAAEAB32F769FC8EE1ADB0D3D_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_DC92F86EAAEAB32F769FC8EE1ADB0D3D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_33CCA862C07B28738CE1C8EE1ADBC756" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_DC92F86EAAEAB32F769FC8EE1ADB0D3D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ForwardContractsMember" xlink:label="loc_us-gaap_ForwardContractsMember_4FEBAC6536EC13032ACBC8EE1ADB440E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_DC92F86EAAEAB32F769FC8EE1ADB0D3D" xlink:to="loc_us-gaap_ForwardContractsMember_4FEBAC6536EC13032ACBC8EE1ADB440E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_InterestRateContractMember" xlink:label="loc_us-gaap_InterestRateContractMember_695ADDBE188A0252D20CC8EE1ADB7A61" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_DC92F86EAAEAB32F769FC8EE1ADB0D3D" xlink:to="loc_us-gaap_InterestRateContractMember_695ADDBE188A0252D20CC8EE1ADB7A61" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_HedgingDesignationAxis" xlink:label="loc_us-gaap_HedgingDesignationAxis_C70C8DB7FD93FCC229BEC8EE1ADB68FA" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_B95E4FA27E50B0273D2CC8EE1ADA0CA2" xlink:to="loc_us-gaap_HedgingDesignationAxis_C70C8DB7FD93FCC229BEC8EE1ADB68FA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_968CB6E9F499ECD07E07C8EE1ADB4610_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_C70C8DB7FD93FCC229BEC8EE1ADB68FA" xlink:to="loc_us-gaap_HedgingDesignationDomain_968CB6E9F499ECD07E07C8EE1ADB4610_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_968CB6E9F499ECD07E07C8EE1ADB4610" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_C70C8DB7FD93FCC229BEC8EE1ADB68FA" xlink:to="loc_us-gaap_HedgingDesignationDomain_968CB6E9F499ECD07E07C8EE1ADB4610" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DesignatedAsHedgingInstrumentMember" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_4E3AB3834B1FA70D0D17C8EE1ADB2750" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_968CB6E9F499ECD07E07C8EE1ADB4610" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_4E3AB3834B1FA70D0D17C8EE1ADB2750" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NondesignatedMember" xlink:label="loc_us-gaap_NondesignatedMember_E2F08AD575CE9C49B6C8C8EE1ADB6FB9" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_968CB6E9F499ECD07E07C8EE1ADB4610" xlink:to="loc_us-gaap_NondesignatedMember_E2F08AD575CE9C49B6C8C8EE1ADB6FB9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_2FAD69386C0913D253FBC8EE1ADBA7B2" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_B95E4FA27E50B0273D2CC8EE1ADA0CA2" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_2FAD69386C0913D253FBC8EE1ADBA7B2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_6811577086875B570B24C8EE1ADB8780_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_2FAD69386C0913D253FBC8EE1ADBA7B2" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_6811577086875B570B24C8EE1ADB8780_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_6811577086875B570B24C8EE1ADB8780" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_2FAD69386C0913D253FBC8EE1ADBA7B2" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_6811577086875B570B24C8EE1ADB8780" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CostOfSalesMember" xlink:label="loc_us-gaap_CostOfSalesMember_6070451834F180C2C32DC8EE1ADCB99A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_6811577086875B570B24C8EE1ADB8780" xlink:to="loc_us-gaap_CostOfSalesMember_6070451834F180C2C32DC8EE1ADCB99A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_InterestExpenseMember" xlink:label="loc_us-gaap_InterestExpenseMember_F97CC045BB9EDA2B02A9C8EE1ADC9E4F" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_6811577086875B570B24C8EE1ADB8780" xlink:to="loc_us-gaap_InterestExpenseMember_F97CC045BB9EDA2B02A9C8EE1ADC9E4F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_3C616ECA5721BE3A957CC8EE1ADCF73D" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_B95E4FA27E50B0273D2CC8EE1ADA0CA2" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_3C616ECA5721BE3A957CC8EE1ADCF73D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_HedgingRelationshipDomain" xlink:label="loc_us-gaap_HedgingRelationshipDomain_3162DE827D034A9CFF4CC8EE1ADC9533_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_3C616ECA5721BE3A957CC8EE1ADCF73D" xlink:to="loc_us-gaap_HedgingRelationshipDomain_3162DE827D034A9CFF4CC8EE1ADC9533_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_HedgingRelationshipDomain" xlink:label="loc_us-gaap_HedgingRelationshipDomain_3162DE827D034A9CFF4CC8EE1ADC9533" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_3C616ECA5721BE3A957CC8EE1ADCF73D" xlink:to="loc_us-gaap_HedgingRelationshipDomain_3162DE827D034A9CFF4CC8EE1ADC9533" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CashFlowHedgingMember" xlink:label="loc_us-gaap_CashFlowHedgingMember_00AB1A18904F3B4AC4D7C8EE1ADC7D33" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_3162DE827D034A9CFF4CC8EE1ADC9533" xlink:to="loc_us-gaap_CashFlowHedgingMember_00AB1A18904F3B4AC4D7C8EE1ADC7D33" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_D55567E7625191CEA68EC8EE1ADC83BD" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_B95E4FA27E50B0273D2CC8EE1ADA0CA2" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_D55567E7625191CEA68EC8EE1ADC83BD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_FF1F2710F5D6D88C89F5C8EE1ADC0164_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_D55567E7625191CEA68EC8EE1ADC83BD" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_FF1F2710F5D6D88C89F5C8EE1ADC0164_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_FF1F2710F5D6D88C89F5C8EE1ADC0164" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_D55567E7625191CEA68EC8EE1ADC83BD" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_FF1F2710F5D6D88C89F5C8EE1ADC0164" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherLiabilitiesMember" xlink:label="loc_us-gaap_OtherLiabilitiesMember_9A45ACD5DD7CDBADAA20C8EE1ADC7EA2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_FF1F2710F5D6D88C89F5C8EE1ADC0164" xlink:to="loc_us-gaap_OtherLiabilitiesMember_9A45ACD5DD7CDBADAA20C8EE1ADC7EA2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DerivativeNumberOfInstrumentsHeld" xlink:label="loc_us-gaap_DerivativeNumberOfInstrumentsHeld_09D53D5B5B7C8ECA3245C8EE1ADCB615" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_9B5387DCB159C60EAE11C8EE1ADC48DA" xlink:to="loc_us-gaap_DerivativeNumberOfInstrumentsHeld_09D53D5B5B7C8ECA3245C8EE1ADCB615" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DerivativeGainLossOnDerivativeNet" xlink:label="loc_us-gaap_DerivativeGainLossOnDerivativeNet_E471074F2E5EF5255893C8EE1ADCDA26" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_9B5387DCB159C60EAE11C8EE1ADC48DA" xlink:to="loc_us-gaap_DerivativeGainLossOnDerivativeNet_E471074F2E5EF5255893C8EE1ADCDA26" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeNet" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeNet_2920F2B0D036CE266C41C8EE1ADC8D8E" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_9B5387DCB159C60EAE11C8EE1ADC48DA" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeNet_2920F2B0D036CE266C41C8EE1ADC8D8E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DerivativeInstrumentsLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortion" xlink:label="loc_us-gaap_DerivativeInstrumentsLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortion_075B2D88CD4BAB80205BC8EE1ADCE860" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_9B5387DCB159C60EAE11C8EE1ADC48DA" xlink:to="loc_us-gaap_DerivativeInstrumentsLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortion_075B2D88CD4BAB80205BC8EE1ADCE860" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DerivativeInstrumentsLossRecognizedInOtherComprehensiveIncomeEffectivePortion" xlink:label="loc_us-gaap_DerivativeInstrumentsLossRecognizedInOtherComprehensiveIncomeEffectivePortion_7312C347851AB89A98D3C8EE1ADC2090" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_9B5387DCB159C60EAE11C8EE1ADC48DA" xlink:to="loc_us-gaap_DerivativeInstrumentsLossRecognizedInOtherComprehensiveIncomeEffectivePortion_7312C347851AB89A98D3C8EE1ADC2090" 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/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountLineItems" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_43186B6C2005AB69513C03A24172AE59" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable" xlink:label="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_D61B38E2259A2DA208A803A24171C7BE" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_43186B6C2005AB69513C03A24172AE59" xlink:to="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_D61B38E2259A2DA208A803A24171C7BE" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_DDD8056FD17F5B5E8D5E03A2417144BE" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_D61B38E2259A2DA208A803A24171C7BE" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_DDD8056FD17F5B5E8D5E03A2417144BE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_283F61BF2888B52B8F8003A24171529B_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_DDD8056FD17F5B5E8D5E03A2417144BE" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_283F61BF2888B52B8F8003A24171529B_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_283F61BF2888B52B8F8003A24171529B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_DDD8056FD17F5B5E8D5E03A2417144BE" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_283F61BF2888B52B8F8003A24171529B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnerMember" xlink:label="loc_us-gaap_LimitedPartnerMember_4154BC002D73E4B62E7E03A24171E76E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_283F61BF2888B52B8F8003A24171529B" xlink:to="loc_us-gaap_LimitedPartnerMember_4154BC002D73E4B62E7E03A24171E76E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_C5C9C88C2B0065AE990103A241719CF2" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_D61B38E2259A2DA208A803A24171C7BE" xlink:to="loc_dei_LegalEntityAxis_C5C9C88C2B0065AE990103A241719CF2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_D2B944A552BA616C77B203A241716B88_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_C5C9C88C2B0065AE990103A241719CF2" xlink:to="loc_dei_EntityDomain_D2B944A552BA616C77B203A241716B88_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_D2B944A552BA616C77B203A241716B88" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_C5C9C88C2B0065AE990103A241719CF2" xlink:to="loc_dei_EntityDomain_D2B944A552BA616C77B203A241716B88" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_5F609319F1B67593266203A24171811B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_D2B944A552BA616C77B203A241716B88" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_5F609319F1B67593266203A24171811B" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_WestlakeChemicalOpCoLPMember" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_F2592DA590A43283189103A24172B2AB" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_D2B944A552BA616C77B203A241716B88" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_F2592DA590A43283189103A24172B2AB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_D1C037EDAFF2140357D003A24172DF21" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_D61B38E2259A2DA208A803A24171C7BE" xlink:to="loc_us-gaap_CounterpartyNameAxis_D1C037EDAFF2140357D003A24172DF21" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_12CFD26A56102465100303A241724BA5_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_D1C037EDAFF2140357D003A24172DF21" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_12CFD26A56102465100303A241724BA5_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_12CFD26A56102465100303A241724BA5" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_D1C037EDAFF2140357D003A24172DF21" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_12CFD26A56102465100303A241724BA5" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_2DF9EC8BF8AF8387AD8603A2417282DD" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_12CFD26A56102465100303A241724BA5" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_2DF9EC8BF8AF8387AD8603A2417282DD" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_WestlakeChemicalOpCoLPMember" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_BB9CB2C7908D26353E8603A24172D2BE" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_12CFD26A56102465100303A241724BA5" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_BB9CB2C7908D26353E8603A24172D2BE" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_WestlakeChemicalOpCoGPLLCMember" xlink:label="loc_wlkp_WestlakeChemicalOpCoGPLLCMember_9415924EF2066155A75603A24172BDF4" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_12CFD26A56102465100303A241724BA5" xlink:to="loc_wlkp_WestlakeChemicalOpCoGPLLCMember_9415924EF2066155A75603A24172BDF4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_A0923A08D8B7E0C5A97503A241727849" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_D61B38E2259A2DA208A803A24171C7BE" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_A0923A08D8B7E0C5A97503A241727849" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_1CAD4787EFCB97F1197803A24172F897_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_A0923A08D8B7E0C5A97503A241727849" xlink:to="loc_us-gaap_RelatedPartyDomain_1CAD4787EFCB97F1197803A24172F897_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_1CAD4787EFCB97F1197803A24172F897" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_A0923A08D8B7E0C5A97503A241727849" xlink:to="loc_us-gaap_RelatedPartyDomain_1CAD4787EFCB97F1197803A24172F897" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="loc_us-gaap_AffiliatedEntityMember_320B87A126A709F1242403A2417283C3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_1CAD4787EFCB97F1197803A24172F897" xlink:to="loc_us-gaap_AffiliatedEntityMember_320B87A126A709F1242403A2417283C3" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_WestlakeChemicalOpCoLPMember" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_8C2DC816A9C71F70E8EC03A241723E16" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_1CAD4787EFCB97F1197803A24172F897" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_8C2DC816A9C71F70E8EC03A241723E16" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedLiabilityCompanyMember" xlink:label="loc_us-gaap_LimitedLiabilityCompanyMember_A4DF1A18628834FEF7C003A2417289B8" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_1CAD4787EFCB97F1197803A24172F897" xlink:to="loc_us-gaap_LimitedLiabilityCompanyMember_A4DF1A18628834FEF7C003A2417289B8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_MajorityOwnedSubsidiaryUnconsolidatedMember" xlink:label="loc_us-gaap_MajorityOwnedSubsidiaryUnconsolidatedMember_DEDEE6E7AF4B3556368703A241720331" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_1CAD4787EFCB97F1197803A24172F897" xlink:to="loc_us-gaap_MajorityOwnedSubsidiaryUnconsolidatedMember_DEDEE6E7AF4B3556368703A241720331" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PaymentsToAcquireLimitedPartnershipInterests" xlink:label="loc_us-gaap_PaymentsToAcquireLimitedPartnershipInterests_F71D8B41ADECD412E02903A24172831B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_43186B6C2005AB69513C03A24172AE59" xlink:to="loc_us-gaap_PaymentsToAcquireLimitedPartnershipInterests_F71D8B41ADECD412E02903A24172831B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PartnersCapitalAccountUnitsSoldInPublicOffering" xlink:label="loc_us-gaap_PartnersCapitalAccountUnitsSoldInPublicOffering_CEE3A187E67D8C0C0BE703A241725E8D" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_43186B6C2005AB69513C03A24172AE59" xlink:to="loc_us-gaap_PartnersCapitalAccountUnitsSoldInPublicOffering_CEE3A187E67D8C0C0BE703A241725E8D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest" xlink:label="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest_C09892B92408268F253003A241721DD9" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_43186B6C2005AB69513C03A24172AE59" xlink:to="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest_C09892B92408268F253003A241721DD9" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_NumberofProductionFacilities" xlink:label="loc_wlkp_NumberofProductionFacilities_55170745B915A5E815DD03A24172879D" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_43186B6C2005AB69513C03A24172AE59" xlink:to="loc_wlkp_NumberofProductionFacilities_55170745B915A5E815DD03A24172879D" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/DescriptionOfBusinessAndBasisOfPresentationPolicies" 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_FB99B88D3EAB1654A62203A2415D99D9" xlink:type="locator" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentInformationTable" xlink:label="loc_dei_DocumentInformationTable_E0F64510238D8EDEF2F403A2415D8B3B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_DocumentInformationLineItems_FB99B88D3EAB1654A62203A2415D99D9" xlink:to="loc_dei_DocumentInformationTable_E0F64510238D8EDEF2F403A2415D8B3B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_B8FD9F06BA6D9885377B03A2415D3AAB" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_DocumentInformationTable_E0F64510238D8EDEF2F403A2415D8B3B" xlink:to="loc_us-gaap_StatementClassOfStockAxis_B8FD9F06BA6D9885377B03A2415D3AAB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_48C6937924C09B18D86603A2415D8A0B_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_B8FD9F06BA6D9885377B03A2415D3AAB" xlink:to="loc_us-gaap_ClassOfStockDomain_48C6937924C09B18D86603A2415D8A0B_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_48C6937924C09B18D86603A2415D8A0B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_B8FD9F06BA6D9885377B03A2415D3AAB" xlink:to="loc_us-gaap_ClassOfStockDomain_48C6937924C09B18D86603A2415D8A0B" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_CommonUnitsMember" xlink:label="loc_wlkp_CommonUnitsMember_74372EA1F14A5C9140A103A2415DE9A1" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_48C6937924C09B18D86603A2415D8A0B" xlink:to="loc_wlkp_CommonUnitsMember_74372EA1F14A5C9140A103A2415DE9A1" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_SubordinatedUnitsMember" xlink:label="loc_wlkp_SubordinatedUnitsMember_8F75B61F62EE74C2548203A2415D1C5E" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_48C6937924C09B18D86603A2415D8A0B" xlink:to="loc_wlkp_SubordinatedUnitsMember_8F75B61F62EE74C2548203A2415D1C5E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentType" xlink:label="loc_dei_DocumentType_42EFB3803C53D9826B6F03A2415DD45E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_FB99B88D3EAB1654A62203A2415D99D9" xlink:to="loc_dei_DocumentType_42EFB3803C53D9826B6F03A2415DD45E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_AmendmentFlag" xlink:label="loc_dei_AmendmentFlag_C0FADA5D0618E7EB73B703A2415D5621" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_FB99B88D3EAB1654A62203A2415D99D9" xlink:to="loc_dei_AmendmentFlag_C0FADA5D0618E7EB73B703A2415D5621" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentPeriodEndDate" xlink:label="loc_dei_DocumentPeriodEndDate_780ECDE0542103B95B4B03A2415DA62E" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_FB99B88D3EAB1654A62203A2415D99D9" xlink:to="loc_dei_DocumentPeriodEndDate_780ECDE0542103B95B4B03A2415DA62E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentFiscalYearFocus" xlink:label="loc_dei_DocumentFiscalYearFocus_A57E3469A7F8BDA3484F03A2415D24A9" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_FB99B88D3EAB1654A62203A2415D99D9" xlink:to="loc_dei_DocumentFiscalYearFocus_A57E3469A7F8BDA3484F03A2415D24A9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentFiscalPeriodFocus" xlink:label="loc_dei_DocumentFiscalPeriodFocus_8B7E566E5E2021A966CB03A2415D9975" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_FB99B88D3EAB1654A62203A2415D99D9" xlink:to="loc_dei_DocumentFiscalPeriodFocus_8B7E566E5E2021A966CB03A2415D9975" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_TradingSymbol" xlink:label="loc_dei_TradingSymbol_D7E544095CD6A803A9EE03A2415DEDA3" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_FB99B88D3EAB1654A62203A2415D99D9" xlink:to="loc_dei_TradingSymbol_D7E544095CD6A803A9EE03A2415DEDA3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityRegistrantName" xlink:label="loc_dei_EntityRegistrantName_5A357F4DB6F5EF27232203A2415D00CA" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_FB99B88D3EAB1654A62203A2415D99D9" xlink:to="loc_dei_EntityRegistrantName_5A357F4DB6F5EF27232203A2415D00CA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityCentralIndexKey" xlink:label="loc_dei_EntityCentralIndexKey_88620C087C7B91F9C36F03A2415D5D20" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_FB99B88D3EAB1654A62203A2415D99D9" xlink:to="loc_dei_EntityCentralIndexKey_88620C087C7B91F9C36F03A2415D5D20" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_CurrentFiscalYearEndDate" xlink:label="loc_dei_CurrentFiscalYearEndDate_C82C690908C69E30107D03A2415D6398" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_FB99B88D3EAB1654A62203A2415D99D9" xlink:to="loc_dei_CurrentFiscalYearEndDate_C82C690908C69E30107D03A2415D6398" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityFilerCategory" xlink:label="loc_dei_EntityFilerCategory_FD6A25A9D08E5B9AD50E03A2415D5B3C" xlink:type="locator" />
    <definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_FB99B88D3EAB1654A62203A2415D99D9" xlink:to="loc_dei_EntityFilerCategory_FD6A25A9D08E5B9AD50E03A2415D5B3C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityCommonStockSharesOutstanding" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_76845CAF30556BF73E6103A2415EB188" xlink:type="locator" />
    <definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_FB99B88D3EAB1654A62203A2415D99D9" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_76845CAF30556BF73E6103A2415EB188" 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/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_93D8593B3BA278E6FE42C9E42284F77F" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_F5519928E8BAC74D05B3C9E422838EE9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_93D8593B3BA278E6FE42C9E42284F77F" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_F5519928E8BAC74D05B3C9E422838EE9" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_9D92723A514F2C85CA66C9E42283AA1F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_F5519928E8BAC74D05B3C9E422838EE9" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_9D92723A514F2C85CA66C9E42283AA1F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_4D3E13789779D39AF135C9E42283EE7A_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_9D92723A514F2C85CA66C9E42283AA1F" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_4D3E13789779D39AF135C9E42283EE7A_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_4D3E13789779D39AF135C9E42283EE7A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_9D92723A514F2C85CA66C9E42283AA1F" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_4D3E13789779D39AF135C9E42283EE7A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_InterestRateContractMember" xlink:label="loc_us-gaap_InterestRateContractMember_1713F711E02F33163B2CC9E422846C96" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_4D3E13789779D39AF135C9E42283EE7A" xlink:to="loc_us-gaap_InterestRateContractMember_1713F711E02F33163B2CC9E422846C96" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_006E967D1117AC973555C9E42284CD9A" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_F5519928E8BAC74D05B3C9E422838EE9" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_006E967D1117AC973555C9E42284CD9A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_624BE4AB8BDEDC97376FC9E42284C58D_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_006E967D1117AC973555C9E42284CD9A" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_624BE4AB8BDEDC97376FC9E42284C58D_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_624BE4AB8BDEDC97376FC9E42284C58D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_006E967D1117AC973555C9E42284CD9A" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_624BE4AB8BDEDC97376FC9E42284C58D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_5844BA27976440B595B8C9E422840B80" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_624BE4AB8BDEDC97376FC9E42284C58D" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_5844BA27976440B595B8C9E422840B80" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_A4C608057AD5DF5C3A48C9E422844C05" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_F5519928E8BAC74D05B3C9E422838EE9" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_A4C608057AD5DF5C3A48C9E422844C05" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_21BC2D28BDB21BDFB934C9E42284B3F3_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_A4C608057AD5DF5C3A48C9E422844C05" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_21BC2D28BDB21BDFB934C9E42284B3F3_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_21BC2D28BDB21BDFB934C9E42284B3F3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_A4C608057AD5DF5C3A48C9E422844C05" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_21BC2D28BDB21BDFB934C9E42284B3F3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_D8F40DEDFD4A34A4B647C9E422843523" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_21BC2D28BDB21BDFB934C9E42284B3F3" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_D8F40DEDFD4A34A4B647C9E422843523" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_InterestRateDerivativeLiabilitiesAtFairValue" xlink:label="loc_us-gaap_InterestRateDerivativeLiabilitiesAtFairValue_7A613F00C8190D346627C9E42284CB41" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_93D8593B3BA278E6FE42C9E42284F77F" xlink:to="loc_us-gaap_InterestRateDerivativeLiabilitiesAtFairValue_7A613F00C8190D346627C9E42284CB41" 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/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_239DBFD521195F3D04C3B4DE94B5C6BB" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_B33BCA7163D1D4E3C10AB4DE94AF86DA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_239DBFD521195F3D04C3B4DE94B5C6BB" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_B33BCA7163D1D4E3C10AB4DE94AF86DA" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_DC80C219CAA28BE65866B4DE94AF82B5" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_B33BCA7163D1D4E3C10AB4DE94AF86DA" xlink:to="loc_us-gaap_DebtInstrumentAxis_DC80C219CAA28BE65866B4DE94AF82B5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_924C4214C0757511F04BB4DE94AF9D94_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_DC80C219CAA28BE65866B4DE94AF82B5" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_924C4214C0757511F04BB4DE94AF9D94_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_924C4214C0757511F04BB4DE94AF9D94" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_DC80C219CAA28BE65866B4DE94AF82B5" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_924C4214C0757511F04BB4DE94AF9D94" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_PromissoryNotes2013Member" xlink:label="loc_wlkp_PromissoryNotes2013Member_0C66C7AE7EFF9A89D049B4DE94AF1B35" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_924C4214C0757511F04BB4DE94AF9D94" xlink:to="loc_wlkp_PromissoryNotes2013Member_0C66C7AE7EFF9A89D049B4DE94AF1B35" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_OpCoRevolverMember" xlink:label="loc_wlkp_OpCoRevolverMember_F1C5E1B541274D668921B4DE94AF6FDC" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_924C4214C0757511F04BB4DE94AF9D94" xlink:to="loc_wlkp_OpCoRevolverMember_F1C5E1B541274D668921B4DE94AF6FDC" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_MLPRevolverMember" xlink:label="loc_wlkp_MLPRevolverMember_459D4A29F5366967EB2CB4DE94AF38D4" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_924C4214C0757511F04BB4DE94AF9D94" xlink:to="loc_wlkp_MLPRevolverMember_459D4A29F5366967EB2CB4DE94AF38D4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_CC4D81B5D02FA25F53C1B4DE94B07942" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_B33BCA7163D1D4E3C10AB4DE94AF86DA" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_CC4D81B5D02FA25F53C1B4DE94B07942" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_1AD692EFA66C3D7837E6B4DE94B0A7D8_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_CC4D81B5D02FA25F53C1B4DE94B07942" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_1AD692EFA66C3D7837E6B4DE94B0A7D8_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_1AD692EFA66C3D7837E6B4DE94B0A7D8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_CC4D81B5D02FA25F53C1B4DE94B07942" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_1AD692EFA66C3D7837E6B4DE94B0A7D8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SeniorNotesMember" xlink:label="loc_us-gaap_SeniorNotesMember_AE26564BDD75630AD5CBB4DE94B0BAED" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_1AD692EFA66C3D7837E6B4DE94B0A7D8" xlink:to="loc_us-gaap_SeniorNotesMember_AE26564BDD75630AD5CBB4DE94B0BAED" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_SeniorUnsecuredRevolvingCreditFacilityMember" xlink:label="loc_wlkp_SeniorUnsecuredRevolvingCreditFacilityMember_899331758BC5BF164150B4DE94B54D2A" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_1AD692EFA66C3D7837E6B4DE94B0A7D8" xlink:to="loc_wlkp_SeniorUnsecuredRevolvingCreditFacilityMember_899331758BC5BF164150B4DE94B54D2A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueByMeasurementBasisAxis" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_F8B7EAA1824963303DB4B4DE94B51B35" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_B33BCA7163D1D4E3C10AB4DE94AF86DA" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_F8B7EAA1824963303DB4B4DE94B51B35" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_9741643798BCE18D4563B4DE94B52198_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_F8B7EAA1824963303DB4B4DE94B51B35" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_9741643798BCE18D4563B4DE94B52198_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_D6E3E949F7A6315B3187B4DE94B5CEF7" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_F8B7EAA1824963303DB4B4DE94B51B35" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_D6E3E949F7A6315B3187B4DE94B5CEF7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_9741643798BCE18D4563B4DE94B52198" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_D6E3E949F7A6315B3187B4DE94B5CEF7" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_9741643798BCE18D4563B4DE94B52198" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_D7A37BD2E044A11A8335B4DE94B5A127" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_D6E3E949F7A6315B3187B4DE94B5CEF7" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_D7A37BD2E044A11A8335B4DE94B5A127" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_538F1B15F4F3E86C9D1CB4DE94B51ABD" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_D6E3E949F7A6315B3187B4DE94B5CEF7" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_538F1B15F4F3E86C9D1CB4DE94B51ABD" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_SeniorNotesFairValueDisclosure" xlink:label="loc_wlkp_SeniorNotesFairValueDisclosure_E2EDFE5DBF544B2D8BD8B4DE94B50C54" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_239DBFD521195F3D04C3B4DE94B5C6BB" xlink:to="loc_wlkp_SeniorNotesFairValueDisclosure_E2EDFE5DBF544B2D8BD8B4DE94B50C54" 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/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CashAndCashEquivalentsLineItems" xlink:label="loc_us-gaap_CashAndCashEquivalentsLineItems_A26554BB5445C8B6851B03A2419646B8" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfCashAndCashEquivalentsTable" xlink:label="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTable_4429BA87C7D0570C598B03A24196099B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_A26554BB5445C8B6851B03A2419646B8" xlink:to="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTable_4429BA87C7D0570C598B03A24196099B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_GainLossOnInvestmentsByCategoryAxis" xlink:label="loc_us-gaap_GainLossOnInvestmentsByCategoryAxis_EEF1211E9F79233C904203A241966953" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTable_4429BA87C7D0570C598B03A24196099B" xlink:to="loc_us-gaap_GainLossOnInvestmentsByCategoryAxis_EEF1211E9F79233C904203A241966953" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_GainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostCategoriesOfInvestmentsDomain" xlink:label="loc_us-gaap_GainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostCategoriesOfInvestmentsDomain_0C93F3C61475978940E003A24196A28F_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_GainLossOnInvestmentsByCategoryAxis_EEF1211E9F79233C904203A241966953" xlink:to="loc_us-gaap_GainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostCategoriesOfInvestmentsDomain_0C93F3C61475978940E003A24196A28F_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_GainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostCategoriesOfInvestmentsDomain" xlink:label="loc_us-gaap_GainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostCategoriesOfInvestmentsDomain_0C93F3C61475978940E003A24196A28F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_GainLossOnInvestmentsByCategoryAxis_EEF1211E9F79233C904203A241966953" xlink:to="loc_us-gaap_GainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostCategoriesOfInvestmentsDomain_0C93F3C61475978940E003A24196A28F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_HeldtomaturitySecuritiesMember" xlink:label="loc_us-gaap_HeldtomaturitySecuritiesMember_DBFF5CFFF65B915C9DDE03A24196410B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostCategoriesOfInvestmentsDomain_0C93F3C61475978940E003A24196A28F" xlink:to="loc_us-gaap_HeldtomaturitySecuritiesMember_DBFF5CFFF65B915C9DDE03A24196410B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashEquivalentsAtCarryingValue_3021B91DE3DC97BD12BA03A24196328B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_A26554BB5445C8B6851B03A2419646B8" xlink:to="loc_us-gaap_CashEquivalentsAtCarryingValue_3021B91DE3DC97BD12BA03A24196328B" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/IncomeTaxes" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/IncomeTaxesDetail" xlink:type="extended" />
  <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/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_3578ACED5A44006B401CB74E6BA82EA5" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_5C2DEAC50186D3ED3AF3B74E6B9C12D5" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_3578ACED5A44006B401CB74E6BA82EA5" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_5C2DEAC50186D3ED3AF3B74E6B9C12D5" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_78B51217B1B5AA592014B74E6B9CC0B2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_5C2DEAC50186D3ED3AF3B74E6B9C12D5" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_78B51217B1B5AA592014B74E6B9CC0B2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_920523DC6BB0EF9A1222B74E6B9CB40A_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_78B51217B1B5AA592014B74E6B9CC0B2" xlink:to="loc_us-gaap_RelatedPartyDomain_920523DC6BB0EF9A1222B74E6B9CB40A_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_920523DC6BB0EF9A1222B74E6B9CB40A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_78B51217B1B5AA592014B74E6B9CC0B2" xlink:to="loc_us-gaap_RelatedPartyDomain_920523DC6BB0EF9A1222B74E6B9CB40A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnerMember" xlink:label="loc_us-gaap_LimitedPartnerMember_1E1D3788DDA925BEEF28B74E6B9CF0F5" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_920523DC6BB0EF9A1222B74E6B9CB40A" xlink:to="loc_us-gaap_LimitedPartnerMember_1E1D3788DDA925BEEF28B74E6B9CF0F5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="loc_us-gaap_AffiliatedEntityMember_5C6C1016B79C0CFF8948B74E6B9C5F3F" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_920523DC6BB0EF9A1222B74E6B9CB40A" xlink:to="loc_us-gaap_AffiliatedEntityMember_5C6C1016B79C0CFF8948B74E6B9C5F3F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_0A42E32CF6FEDDB2AF00B74E6BA1C05E" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_5C2DEAC50186D3ED3AF3B74E6B9C12D5" xlink:to="loc_dei_LegalEntityAxis_0A42E32CF6FEDDB2AF00B74E6BA1C05E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_074C4D8767B722C19627B74E6BA2E18F_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_0A42E32CF6FEDDB2AF00B74E6BA1C05E" xlink:to="loc_dei_EntityDomain_074C4D8767B722C19627B74E6BA2E18F_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_074C4D8767B722C19627B74E6BA2E18F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_0A42E32CF6FEDDB2AF00B74E6BA1C05E" xlink:to="loc_dei_EntityDomain_074C4D8767B722C19627B74E6BA2E18F" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_WestlakeChemicalOpCoLPMember" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_293CE3363D6097119A32B74E6BA28866" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_074C4D8767B722C19627B74E6BA2E18F" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_293CE3363D6097119A32B74E6BA28866" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_OpCoRevolverMember" xlink:label="loc_wlkp_OpCoRevolverMember_B0670960609DF3A0B12CB74E6BA28B44" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_074C4D8767B722C19627B74E6BA2E18F" xlink:to="loc_wlkp_OpCoRevolverMember_B0670960609DF3A0B12CB74E6BA28B44" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_53440C1165F359B51E80B74E6BA2E4B0" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_5C2DEAC50186D3ED3AF3B74E6B9C12D5" xlink:to="loc_us-gaap_CounterpartyNameAxis_53440C1165F359B51E80B74E6BA2E4B0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_CD2615899747FB3255D9B74E6BA25E91_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_53440C1165F359B51E80B74E6BA2E4B0" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_CD2615899747FB3255D9B74E6BA25E91_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_CD2615899747FB3255D9B74E6BA25E91" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_53440C1165F359B51E80B74E6BA2E4B0" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_CD2615899747FB3255D9B74E6BA25E91" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_WestlakeChemicalOpCoLPMember" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_249F9135BD7C364C5D45B74E6BA22C5C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_CD2615899747FB3255D9B74E6BA25E91" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_249F9135BD7C364C5D45B74E6BA22C5C" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_F9D9A1E3191DEAB97075B74E6BA29594" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_CD2615899747FB3255D9B74E6BA25E91" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_F9D9A1E3191DEAB97075B74E6BA29594" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_8A1F4A7CDA422ABD9701B74E6BA2F08F" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_5C2DEAC50186D3ED3AF3B74E6B9C12D5" xlink:to="loc_us-gaap_DebtInstrumentAxis_8A1F4A7CDA422ABD9701B74E6BA2F08F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_D34305DFA04167E8CE08B74E6BA252A4_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_8A1F4A7CDA422ABD9701B74E6BA2F08F" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_D34305DFA04167E8CE08B74E6BA252A4_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_D34305DFA04167E8CE08B74E6BA252A4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_8A1F4A7CDA422ABD9701B74E6BA2F08F" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_D34305DFA04167E8CE08B74E6BA252A4" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_PromissoryNotes2013Member" xlink:label="loc_wlkp_PromissoryNotes2013Member_16AC25F90CC59B274F68B74E6BA28756" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_D34305DFA04167E8CE08B74E6BA252A4" xlink:to="loc_wlkp_PromissoryNotes2013Member_16AC25F90CC59B274F68B74E6BA28756" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_OpCoRevolverMember" xlink:label="loc_wlkp_OpCoRevolverMember_0DF9F33C82F1595618EBB74E6BA26817" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_D34305DFA04167E8CE08B74E6BA252A4" xlink:to="loc_wlkp_OpCoRevolverMember_0DF9F33C82F1595618EBB74E6BA26817" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_WestlakeChemicalOpCoLPMember" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_7C78E5A8217807313535B74E6BA2B505" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_D34305DFA04167E8CE08B74E6BA252A4" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_7C78E5A8217807313535B74E6BA2B505" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_MLPRevolverMember" xlink:label="loc_wlkp_MLPRevolverMember_94146D6257B4E0F2A641B74E6BA2CE69" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_D34305DFA04167E8CE08B74E6BA252A4" xlink:to="loc_wlkp_MLPRevolverMember_94146D6257B4E0F2A641B74E6BA2CE69" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_F628F2088DA4BFA53FE7B74E6BA31EEF" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_5C2DEAC50186D3ED3AF3B74E6B9C12D5" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_F628F2088DA4BFA53FE7B74E6BA31EEF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_832AA45D7DEFCFA2C83DB74E6BA3B6F5_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_F628F2088DA4BFA53FE7B74E6BA31EEF" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_832AA45D7DEFCFA2C83DB74E6BA3B6F5_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_832AA45D7DEFCFA2C83DB74E6BA3B6F5" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_F628F2088DA4BFA53FE7B74E6BA31EEF" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_832AA45D7DEFCFA2C83DB74E6BA3B6F5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LineOfCreditMember" xlink:label="loc_us-gaap_LineOfCreditMember_D869B808C9A2C7696818B74E6BA3C341" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_832AA45D7DEFCFA2C83DB74E6BA3B6F5" xlink:to="loc_us-gaap_LineOfCreditMember_D869B808C9A2C7696818B74E6BA3C341" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SeniorNotesMember" xlink:label="loc_us-gaap_SeniorNotesMember_99835B969EE8189A5F66B74E6BA37B59" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_832AA45D7DEFCFA2C83DB74E6BA3B6F5" xlink:to="loc_us-gaap_SeniorNotesMember_99835B969EE8189A5F66B74E6BA37B59" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_SeniorUnsecuredRevolvingCreditFacilityMember" xlink:label="loc_wlkp_SeniorUnsecuredRevolvingCreditFacilityMember_62191D6B2E9237CC0E0CB74E6BA3ACCF" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_832AA45D7DEFCFA2C83DB74E6BA3B6F5" xlink:to="loc_wlkp_SeniorUnsecuredRevolvingCreditFacilityMember_62191D6B2E9237CC0E0CB74E6BA3ACCF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_VariableRateAxis" xlink:label="loc_us-gaap_VariableRateAxis_B97B69BDFF31F533F287B74E6BA35F0D" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_5C2DEAC50186D3ED3AF3B74E6B9C12D5" xlink:to="loc_us-gaap_VariableRateAxis_B97B69BDFF31F533F287B74E6BA35F0D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="loc_us-gaap_VariableRateDomain_490174AB525588AAB97DB74E6BA3C90A_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_B97B69BDFF31F533F287B74E6BA35F0D" xlink:to="loc_us-gaap_VariableRateDomain_490174AB525588AAB97DB74E6BA3C90A_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="loc_us-gaap_VariableRateDomain_490174AB525588AAB97DB74E6BA3C90A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_B97B69BDFF31F533F287B74E6BA35F0D" xlink:to="loc_us-gaap_VariableRateDomain_490174AB525588AAB97DB74E6BA3C90A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PrimeRateMember" xlink:label="loc_us-gaap_PrimeRateMember_E07E9CE92FD0A2EC9EECB74E6BA33927" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_490174AB525588AAB97DB74E6BA3C90A" xlink:to="loc_us-gaap_PrimeRateMember_E07E9CE92FD0A2EC9EECB74E6BA33927" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember" xlink:label="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_BEA449E34FD68C677AE7B74E6BA356EE" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_490174AB525588AAB97DB74E6BA3C90A" xlink:to="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_BEA449E34FD68C677AE7B74E6BA356EE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_9C21CAB14D82ADEDF1C8B74E6BA3CEFB" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_5C2DEAC50186D3ED3AF3B74E6B9C12D5" xlink:to="loc_us-gaap_RangeAxis_9C21CAB14D82ADEDF1C8B74E6BA3CEFB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_DB3402E5F592328D2336B74E6BA3DB6D_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_9C21CAB14D82ADEDF1C8B74E6BA3CEFB" xlink:to="loc_us-gaap_RangeMember_DB3402E5F592328D2336B74E6BA3DB6D_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_DB3402E5F592328D2336B74E6BA3DB6D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_9C21CAB14D82ADEDF1C8B74E6BA3CEFB" xlink:to="loc_us-gaap_RangeMember_DB3402E5F592328D2336B74E6BA3DB6D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_6216C7DC717DBF49D0E6B74E6BA31264" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_DB3402E5F592328D2336B74E6BA3DB6D" xlink:to="loc_us-gaap_MinimumMember_6216C7DC717DBF49D0E6B74E6BA31264" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_4542B2F28D90258AA4EDB74E6BA81BE0" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_DB3402E5F592328D2336B74E6BA3DB6D" xlink:to="loc_us-gaap_MaximumMember_4542B2F28D90258AA4EDB74E6BA81BE0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DueToRelatedPartiesNoncurrent" xlink:label="loc_us-gaap_DueToRelatedPartiesNoncurrent_578072F94A2B77FBF994B74E6BA98772" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_3578ACED5A44006B401CB74E6BA82EA5" xlink:to="loc_us-gaap_DueToRelatedPartiesNoncurrent_578072F94A2B77FBF994B74E6BA98772" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_NumberofIntercompanyPromissoryNotes" xlink:label="loc_wlkp_NumberofIntercompanyPromissoryNotes_E4CD9D828B669DF8A15DB74E6BA9B139" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_3578ACED5A44006B401CB74E6BA82EA5" xlink:to="loc_wlkp_NumberofIntercompanyPromissoryNotes_E4CD9D828B669DF8A15DB74E6BA9B139" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_C551F2EA0C3289D03374B74E6BA9F039" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_3578ACED5A44006B401CB74E6BA82EA5" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_C551F2EA0C3289D03374B74E6BA9F039" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_746ECCCE0D4B03BE6876B74E6BA908BE" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_3578ACED5A44006B401CB74E6BA82EA5" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_746ECCCE0D4B03BE6876B74E6BA908BE" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_MaximumConsolidatedLeverageRatioDuringOneYearFollowingAcquisitions" xlink:label="loc_wlkp_MaximumConsolidatedLeverageRatioDuringOneYearFollowingAcquisitions_5A28B6E545F948C11B4AB74E6BA9D7E2" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_3578ACED5A44006B401CB74E6BA82EA5" xlink:to="loc_wlkp_MaximumConsolidatedLeverageRatioDuringOneYearFollowingAcquisitions_5A28B6E545F948C11B4AB74E6BA9D7E2" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_LeverageCapitalRatioRequiredDuringOtherPeriods" xlink:label="loc_wlkp_LeverageCapitalRatioRequiredDuringOtherPeriods_08A856FB1EE91B69EEBBB74E6BA92FA2" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_3578ACED5A44006B401CB74E6BA82EA5" xlink:to="loc_wlkp_LeverageCapitalRatioRequiredDuringOtherPeriods_08A856FB1EE91B69EEBBB74E6BA92FA2" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersAdditionalOwnershipInterest" xlink:label="loc_wlkp_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersAdditionalOwnershipInterest_428925516BD0F2F5EF21B74E6BA9F80E" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_3578ACED5A44006B401CB74E6BA82EA5" xlink:to="loc_wlkp_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersAdditionalOwnershipInterest_428925516BD0F2F5EF21B74E6BA9F80E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PaymentsToAcquireLimitedPartnershipInterests" xlink:label="loc_us-gaap_PaymentsToAcquireLimitedPartnershipInterests_04BE24CBF33A450FEFC7B74E6BA9AAD3" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_3578ACED5A44006B401CB74E6BA82EA5" xlink:to="loc_us-gaap_PaymentsToAcquireLimitedPartnershipInterests_04BE24CBF33A450FEFC7B74E6BA9AAD3" 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/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ConcentrationRiskLineItems" xlink:label="loc_us-gaap_ConcentrationRiskLineItems_8399CDDAD336E543CC79B4352B09ECA2" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ConcentrationRiskTable" xlink:label="loc_us-gaap_ConcentrationRiskTable_A80E36AB091EB019D544B4352B03A51A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_8399CDDAD336E543CC79B4352B09ECA2" xlink:to="loc_us-gaap_ConcentrationRiskTable_A80E36AB091EB019D544B4352B03A51A" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_4C55AA81B52943AD0D2CB4352B032F87" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_A80E36AB091EB019D544B4352B03A51A" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_4C55AA81B52943AD0D2CB4352B032F87" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_13A0CC06BE0439E257C1B4352B03017E_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_4C55AA81B52943AD0D2CB4352B032F87" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_13A0CC06BE0439E257C1B4352B03017E_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_13A0CC06BE0439E257C1B4352B03017E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_4C55AA81B52943AD0D2CB4352B032F87" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_13A0CC06BE0439E257C1B4352B03017E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SalesRevenueNetMember" xlink:label="loc_us-gaap_SalesRevenueNetMember_9BDF03CE7B7AA3708A32B4352B038986" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_13A0CC06BE0439E257C1B4352B03017E" xlink:to="loc_us-gaap_SalesRevenueNetMember_9BDF03CE7B7AA3708A32B4352B038986" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_DBAD643E073FFC70EBD3B4352B037A4E" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_A80E36AB091EB019D544B4352B03A51A" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_DBAD643E073FFC70EBD3B4352B037A4E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_54C3B023E4BB0E0CDB34B4352B03465D_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_DBAD643E073FFC70EBD3B4352B037A4E" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_54C3B023E4BB0E0CDB34B4352B03465D_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_54C3B023E4BB0E0CDB34B4352B03465D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_DBAD643E073FFC70EBD3B4352B037A4E" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_54C3B023E4BB0E0CDB34B4352B03465D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CustomerConcentrationRiskMember" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_2C54064D4ECBEDA8774AB4352B034791" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_54C3B023E4BB0E0CDB34B4352B03465D" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_2C54064D4ECBEDA8774AB4352B034791" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_MajorCustomersAxis" xlink:label="loc_us-gaap_MajorCustomersAxis_C37307FDB26ACD04CFBFB4352B03CB5D" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_A80E36AB091EB019D544B4352B03A51A" xlink:to="loc_us-gaap_MajorCustomersAxis_C37307FDB26ACD04CFBFB4352B03CB5D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="loc_us-gaap_NameOfMajorCustomerDomain_2B33BFC906CC2BE665B5B4352B09542B_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MajorCustomersAxis_C37307FDB26ACD04CFBFB4352B03CB5D" xlink:to="loc_us-gaap_NameOfMajorCustomerDomain_2B33BFC906CC2BE665B5B4352B09542B_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="loc_us-gaap_NameOfMajorCustomerDomain_2B33BFC906CC2BE665B5B4352B09542B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MajorCustomersAxis_C37307FDB26ACD04CFBFB4352B03CB5D" xlink:to="loc_us-gaap_NameOfMajorCustomerDomain_2B33BFC906CC2BE665B5B4352B09542B" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_8EB1F8D8FA20EA5925DBB4352B0919B2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NameOfMajorCustomerDomain_2B33BFC906CC2BE665B5B4352B09542B" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_8EB1F8D8FA20EA5925DBB4352B0919B2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_8C42AB9811D0ABFF7609B4352B09B3C4" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_A80E36AB091EB019D544B4352B03A51A" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_8C42AB9811D0ABFF7609B4352B09B3C4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_BCBCE5062D52931DC7BAB4352B095551_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_8C42AB9811D0ABFF7609B4352B09B3C4" xlink:to="loc_us-gaap_RelatedPartyDomain_BCBCE5062D52931DC7BAB4352B095551_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_BCBCE5062D52931DC7BAB4352B095551" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_8C42AB9811D0ABFF7609B4352B09B3C4" xlink:to="loc_us-gaap_RelatedPartyDomain_BCBCE5062D52931DC7BAB4352B095551" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="loc_us-gaap_AffiliatedEntityMember_6E37A921957B5DC92349B4352B091D6B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_BCBCE5062D52931DC7BAB4352B095551" xlink:to="loc_us-gaap_AffiliatedEntityMember_6E37A921957B5DC92349B4352B091D6B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_67A2958F378F57DFEDD0B4352B097947" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_8399CDDAD336E543CC79B4352B09ECA2" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_67A2958F378F57DFEDD0B4352B097947" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/NetIncomePerLimitedPartnerUnit" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/NetIncomePerLimitedPartnerUnitBasicAndDilutedIncomePerLimitedPartnerUnitDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountLineItems" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_2072F2CCF8095450988EB4DE9578F035" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable" xlink:label="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_DE41B92D223D7D95530FB4DE9578A74D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_2072F2CCF8095450988EB4DE9578F035" xlink:to="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_DE41B92D223D7D95530FB4DE9578A74D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_4A7C399A46F0CD28F460B4DE95782741" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_DE41B92D223D7D95530FB4DE9578A74D" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_4A7C399A46F0CD28F460B4DE95782741" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_690AA350422146BDE84AB4DE957835B2_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_4A7C399A46F0CD28F460B4DE95782741" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_690AA350422146BDE84AB4DE957835B2_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_690AA350422146BDE84AB4DE957835B2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_4A7C399A46F0CD28F460B4DE95782741" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_690AA350422146BDE84AB4DE957835B2" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_CommonUnitsMember" xlink:label="loc_wlkp_CommonUnitsMember_55C135A0E72AA7CC0092B4DE95787BC4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_690AA350422146BDE84AB4DE957835B2" xlink:to="loc_wlkp_CommonUnitsMember_55C135A0E72AA7CC0092B4DE95787BC4" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_SubordinatedUnitsMember" xlink:label="loc_wlkp_SubordinatedUnitsMember_39F14A85D26CFE820E6CB4DE957872D7" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_690AA350422146BDE84AB4DE957835B2" xlink:to="loc_wlkp_SubordinatedUnitsMember_39F14A85D26CFE820E6CB4DE957872D7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DistributedEarnings" xlink:label="loc_us-gaap_DistributedEarnings_7AD5134DC5BE542BC4ABB4DE95787963" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_2072F2CCF8095450988EB4DE9578F035" xlink:to="loc_us-gaap_DistributedEarnings_7AD5134DC5BE542BC4ABB4DE95787963" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_UndistributedEarnings" xlink:label="loc_us-gaap_UndistributedEarnings_D546AD7B0F2786F05A8EB4DE9578C3A8" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_2072F2CCF8095450988EB4DE9578F035" xlink:to="loc_us-gaap_UndistributedEarnings_D546AD7B0F2786F05A8EB4DE9578C3A8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_35D204B680BAA80D739EB4DE95783E35" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_2072F2CCF8095450988EB4DE9578F035" xlink:to="loc_us-gaap_NetIncomeLoss_35D204B680BAA80D739EB4DE95783E35" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract" xlink:label="loc_us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract_9E960984DAAA2CC79D93B4DE95792334" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_2072F2CCF8095450988EB4DE9578F035" xlink:to="loc_us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract_9E960984DAAA2CC79D93B4DE95792334" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted" xlink:label="loc_us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted_4F1E43E8737C3D210C90B4DE95794CC9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract_9E960984DAAA2CC79D93B4DE95792334" xlink:to="loc_us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted_4F1E43E8737C3D210C90B4DE95794CC9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EarningsPerShareBasicAndDilutedAbstract" xlink:label="loc_us-gaap_EarningsPerShareBasicAndDilutedAbstract_ECDCA7E0F39407026865B4DE957969E0" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_2072F2CCF8095450988EB4DE9578F035" xlink:to="loc_us-gaap_EarningsPerShareBasicAndDilutedAbstract_ECDCA7E0F39407026865B4DE957969E0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EarningsPerShareBasicAndDiluted" xlink:label="loc_us-gaap_EarningsPerShareBasicAndDiluted_0B169ED0E6923C2C3502B4DE95797AEB" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAndDilutedAbstract_ECDCA7E0F39407026865B4DE957969E0" xlink:to="loc_us-gaap_EarningsPerShareBasicAndDiluted_0B169ED0E6923C2C3502B4DE95797AEB" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/NetIncomePerLimitedPartnerUnitDistributionsDeclaredDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DistributionMadeToLimitedPartnerLineItems" xlink:label="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_3BD1D56833845FB34F65AFD897510F2E" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DistributionsMadeToLimitedPartnerTable" xlink:label="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_73F65A0C9C1E5595D6C4AFD89751AC84" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_3BD1D56833845FB34F65AFD897510F2E" xlink:to="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_73F65A0C9C1E5595D6C4AFD89751AC84" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_46D079E0D23110890383B08C9D85FF49" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_73F65A0C9C1E5595D6C4AFD89751AC84" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_46D079E0D23110890383B08C9D85FF49" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_D5F97AED681E4C7F8204B08C9DAD364C_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_46D079E0D23110890383B08C9D85FF49" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_D5F97AED681E4C7F8204B08C9DAD364C_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_D5F97AED681E4C7F8204B08C9DAD364C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_46D079E0D23110890383B08C9D85FF49" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_D5F97AED681E4C7F8204B08C9DAD364C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaap_SubsequentEventMember_2176B16C629C164C9EE8B08C9EA6B311" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_D5F97AED681E4C7F8204B08C9DAD364C" xlink:to="loc_us-gaap_SubsequentEventMember_2176B16C629C164C9EE8B08C9EA6B311" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_96EAB41A909C9FA43161AFD897510544" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_73F65A0C9C1E5595D6C4AFD89751AC84" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_96EAB41A909C9FA43161AFD897510544" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_29E90A9B0A94031C5DB9AFD89751F935_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_96EAB41A909C9FA43161AFD897510544" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_29E90A9B0A94031C5DB9AFD89751F935_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_29E90A9B0A94031C5DB9AFD89751F935" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_96EAB41A909C9FA43161AFD897510544" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_29E90A9B0A94031C5DB9AFD89751F935" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_WestlakeChemicalOpCoLPMember" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_1AFDCAEACE31979EAC79AFD89751854C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_29E90A9B0A94031C5DB9AFD89751F935" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_1AFDCAEACE31979EAC79AFD89751854C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit" xlink:label="loc_us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit_D7A720A58360BE493BFAAFD8975175F5" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_3BD1D56833845FB34F65AFD897510F2E" xlink:to="loc_us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit_D7A720A58360BE493BFAAFD8975175F5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DistributionMadeToLimitedPartnerCashDistributionsDeclared" xlink:label="loc_us-gaap_DistributionMadeToLimitedPartnerCashDistributionsDeclared_EBDB76076086CC1A15F7AFD897511960" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_3BD1D56833845FB34F65AFD897510F2E" xlink:to="loc_us-gaap_DistributionMadeToLimitedPartnerCashDistributionsDeclared_EBDB76076086CC1A15F7AFD897511960" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/NetIncomePerLimitedPartnerUnitIncomeInExcessOfDistributionDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_EA7EDA140F07FB84BE3CB4DE9581A717" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_FF2D58FCB5C9522DA781B4DE95816321" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_EA7EDA140F07FB84BE3CB4DE9581A717" xlink:to="loc_us-gaap_StatementTable_FF2D58FCB5C9522DA781B4DE95816321" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_7CA840AFE35F69A2CA8DB4DE9581F218" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_FF2D58FCB5C9522DA781B4DE95816321" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_7CA840AFE35F69A2CA8DB4DE9581F218" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_7A05F1AB1C224BC60AB9B4DE9581B7DB_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_7CA840AFE35F69A2CA8DB4DE9581F218" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_7A05F1AB1C224BC60AB9B4DE9581B7DB_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_7A05F1AB1C224BC60AB9B4DE9581B7DB" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_7CA840AFE35F69A2CA8DB4DE9581F218" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_7A05F1AB1C224BC60AB9B4DE9581B7DB" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_CommonUnitsMember" xlink:label="loc_wlkp_CommonUnitsMember_47885B346C5780A4B516B4DE9581BBC9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_7A05F1AB1C224BC60AB9B4DE9581B7DB" xlink:to="loc_wlkp_CommonUnitsMember_47885B346C5780A4B516B4DE9581BBC9" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_SubordinatedUnitsMember" xlink:label="loc_wlkp_SubordinatedUnitsMember_E904F6666608478E0347B4DE9581A0F3" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_7A05F1AB1C224BC60AB9B4DE9581B7DB" xlink:to="loc_wlkp_SubordinatedUnitsMember_E904F6666608478E0347B4DE9581A0F3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_AF934AB929A9A0677109B4DE95814400" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_EA7EDA140F07FB84BE3CB4DE9581A717" xlink:to="loc_us-gaap_NetIncomeLoss_AF934AB929A9A0677109B4DE95814400" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DistributedEarnings" xlink:label="loc_us-gaap_DistributedEarnings_0F6555E9A37BC4601F46B4DE95817AD1" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_EA7EDA140F07FB84BE3CB4DE9581A717" xlink:to="loc_us-gaap_DistributedEarnings_0F6555E9A37BC4601F46B4DE95817AD1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_UndistributedEarnings" xlink:label="loc_us-gaap_UndistributedEarnings_C3D865B8F962D42C46C6B4DE9582500D" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_EA7EDA140F07FB84BE3CB4DE9581A717" xlink:to="loc_us-gaap_UndistributedEarnings_C3D865B8F962D42C46C6B4DE9582500D" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://www.westlake.com/role/NetIncomePerLimitedPartnerUnitTables" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/OtherAssets" xlink:type="extended" />
  <definitionLink xlink:role="http://www.westlake.com/role/OtherAssetsDetail" xlink:type="extended">
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityInformationLineItems" xlink:label="loc_dei_EntityInformationLineItems_B5666A40E06CDF47AC9EB407DB898E43" xlink:type="locator" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntitiesTable" xlink:label="loc_dei_EntitiesTable_2FCEF60CB4FCF585CC41B407DB88175B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityInformationLineItems_B5666A40E06CDF47AC9EB407DB898E43" xlink:to="loc_dei_EntitiesTable_2FCEF60CB4FCF585CC41B407DB88175B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_47D0DC988C250ACC257BB407DB88A9F4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_2FCEF60CB4FCF585CC41B407DB88175B" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_47D0DC988C250ACC257BB407DB88A9F4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_AD6F48544C064D9B8EBEB407DB880A30_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_47D0DC988C250ACC257BB407DB88A9F4" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_AD6F48544C064D9B8EBEB407DB880A30_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_AD6F48544C064D9B8EBEB407DB880A30" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_47D0DC988C250ACC257BB407DB88A9F4" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_AD6F48544C064D9B8EBEB407DB880A30" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherAssetsMember" xlink:label="loc_us-gaap_OtherAssetsMember_23CB42499B0F529949FDB407DB883C2C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_AD6F48544C064D9B8EBEB407DB880A30" xlink:to="loc_us-gaap_OtherAssetsMember_23CB42499B0F529949FDB407DB883C2C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AdjustmentForAmortization" xlink:label="loc_us-gaap_AdjustmentForAmortization_F05FBE126345484293B1B407DB898DDF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_B5666A40E06CDF47AC9EB407DB898E43" xlink:to="loc_us-gaap_AdjustmentForAmortization_F05FBE126345484293B1B407DB898DDF" xlink:type="arc" />
  </definitionLink>
  <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/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_E54AD4262F99D44CBF48B407DB6779FF" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_103F190A2C74EBA1B0B7B407DB66A2AA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_E54AD4262F99D44CBF48B407DB6779FF" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_103F190A2C74EBA1B0B7B407DB66A2AA" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_06F95C26A149BFC5C149B407DB664A13" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_103F190A2C74EBA1B0B7B407DB66A2AA" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_06F95C26A149BFC5C149B407DB664A13" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_820CDFF350AB78BD0628B407DB66B22C_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_06F95C26A149BFC5C149B407DB664A13" xlink:to="loc_us-gaap_RelatedPartyDomain_820CDFF350AB78BD0628B407DB66B22C_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_820CDFF350AB78BD0628B407DB66B22C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_06F95C26A149BFC5C149B407DB664A13" xlink:to="loc_us-gaap_RelatedPartyDomain_820CDFF350AB78BD0628B407DB66B22C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="loc_us-gaap_AffiliatedEntityMember_BFBFBEA0023A26F51763B407DB664A15" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_820CDFF350AB78BD0628B407DB66B22C" xlink:to="loc_us-gaap_AffiliatedEntityMember_BFBFBEA0023A26F51763B407DB664A15" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_14D3ECA28FA496C78990B407DB6698C4" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_103F190A2C74EBA1B0B7B407DB66A2AA" xlink:to="loc_us-gaap_CounterpartyNameAxis_14D3ECA28FA496C78990B407DB6698C4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_A16792F1EA12B55B45B3B407DB6648CA_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_14D3ECA28FA496C78990B407DB6698C4" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_A16792F1EA12B55B45B3B407DB6648CA_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_A16792F1EA12B55B45B3B407DB6648CA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_14D3ECA28FA496C78990B407DB6698C4" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_A16792F1EA12B55B45B3B407DB6648CA" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_AD7AE3126E80EA8C27B5B407DB6689D7" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_A16792F1EA12B55B45B3B407DB6648CA" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_AD7AE3126E80EA8C27B5B407DB6689D7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AccountsReceivableRelatedPartiesCurrent" xlink:label="loc_us-gaap_AccountsReceivableRelatedPartiesCurrent_6D37C86D4165E6B8BA2BB407DB67E0AE" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_E54AD4262F99D44CBF48B407DB6779FF" xlink:to="loc_us-gaap_AccountsReceivableRelatedPartiesCurrent_6D37C86D4165E6B8BA2BB407DB67E0AE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AccountsPayableRelatedPartiesCurrent" xlink:label="loc_us-gaap_AccountsPayableRelatedPartiesCurrent_7BA2CAE511924BCB66FBB407DB673B61" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_E54AD4262F99D44CBF48B407DB6779FF" xlink:to="loc_us-gaap_AccountsPayableRelatedPartiesCurrent_7BA2CAE511924BCB66FBB407DB673B61" 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/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_B90F790FF412D339CBD7B407DB72CA4D" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_741F223D7BE4D0D16741B407DB723152" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_B90F790FF412D339CBD7B407DB72CA4D" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_741F223D7BE4D0D16741B407DB723152" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_AD5EE08F6571E9B3C48EB407DB72854E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_741F223D7BE4D0D16741B407DB723152" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_AD5EE08F6571E9B3C48EB407DB72854E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_181C53FEB10C528F9C25B407DB721ED6_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_AD5EE08F6571E9B3C48EB407DB72854E" xlink:to="loc_us-gaap_RelatedPartyDomain_181C53FEB10C528F9C25B407DB721ED6_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_181C53FEB10C528F9C25B407DB721ED6" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_AD5EE08F6571E9B3C48EB407DB72854E" xlink:to="loc_us-gaap_RelatedPartyDomain_181C53FEB10C528F9C25B407DB721ED6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="loc_us-gaap_AffiliatedEntityMember_5CD1588726D7AFAD47EBB407DB726A3B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_181C53FEB10C528F9C25B407DB721ED6" xlink:to="loc_us-gaap_AffiliatedEntityMember_5CD1588726D7AFAD47EBB407DB726A3B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_8850F643A5EA4C5173B9B407DB72F539" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_741F223D7BE4D0D16741B407DB723152" xlink:to="loc_us-gaap_CounterpartyNameAxis_8850F643A5EA4C5173B9B407DB72F539" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_27C1F0BEFE787C0A3A79B407DB72E8E8_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_8850F643A5EA4C5173B9B407DB72F539" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_27C1F0BEFE787C0A3A79B407DB72E8E8_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_27C1F0BEFE787C0A3A79B407DB72E8E8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_8850F643A5EA4C5173B9B407DB72F539" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_27C1F0BEFE787C0A3A79B407DB72E8E8" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_8A8B79899B6D0762AD58B407DB72F4F9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_27C1F0BEFE787C0A3A79B407DB72E8E8" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_8A8B79899B6D0762AD58B407DB72F4F9" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_RelatedPartiesAmountInCostOfSalesFeedstockPurchased" xlink:label="loc_wlkp_RelatedPartiesAmountInCostOfSalesFeedstockPurchased_9A5D445719093FCF9101B407DB722B85" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_B90F790FF412D339CBD7B407DB72CA4D" xlink:to="loc_wlkp_RelatedPartiesAmountInCostOfSalesFeedstockPurchased_9A5D445719093FCF9101B407DB722B85" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_CostOfGoodsSoldOther" xlink:label="loc_wlkp_CostOfGoodsSoldOther_C3400741B35CC5B9E0DAB407DB72FB63" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_B90F790FF412D339CBD7B407DB72CA4D" xlink:to="loc_wlkp_CostOfGoodsSoldOther_C3400741B35CC5B9E0DAB407DB72FB63" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CostOfGoodsSold" xlink:label="loc_us-gaap_CostOfGoodsSold_F8452618F87C94528E75B407DB725DCC" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_B90F790FF412D339CBD7B407DB72CA4D" xlink:to="loc_us-gaap_CostOfGoodsSold_F8452618F87C94528E75B407DB725DCC" 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/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_B2A973D7A7C9278A07A103A2419B3979" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_011AC87BD3C6A495CF6D03A2419BF816" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_B2A973D7A7C9278A07A103A2419B3979" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_011AC87BD3C6A495CF6D03A2419BF816" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_B4F0E0BCB790620D61FA03A2419BF498" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_011AC87BD3C6A495CF6D03A2419BF816" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_B4F0E0BCB790620D61FA03A2419BF498" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_A1C5D3A4A0552170DA7E03A2419B754C_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_B4F0E0BCB790620D61FA03A2419BF498" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_A1C5D3A4A0552170DA7E03A2419B754C_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_A1C5D3A4A0552170DA7E03A2419B754C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_B4F0E0BCB790620D61FA03A2419BF498" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_A1C5D3A4A0552170DA7E03A2419B754C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AccruedLiabilitiesMember" xlink:label="loc_us-gaap_AccruedLiabilitiesMember_C4C27DB76FBD5AD8F73603A2419BE6B0" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_A1C5D3A4A0552170DA7E03A2419B754C" xlink:to="loc_us-gaap_AccruedLiabilitiesMember_C4C27DB76FBD5AD8F73603A2419BE6B0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_B66847FDDC55534512A703A2419BF485" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_011AC87BD3C6A495CF6D03A2419BF816" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_B66847FDDC55534512A703A2419BF485" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_9FC93910D32CA459571703A2419B4BE6_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_B66847FDDC55534512A703A2419BF485" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_9FC93910D32CA459571703A2419B4BE6_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_9FC93910D32CA459571703A2419B4BE6" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_B66847FDDC55534512A703A2419BF485" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_9FC93910D32CA459571703A2419B4BE6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpenseMember" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpenseMember_828875B1DC36E5D770C103A2419B5E1E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_9FC93910D32CA459571703A2419B4BE6" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpenseMember_828875B1DC36E5D770C103A2419B5E1E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2994A174464709A26A1A03A2419B9397" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_011AC87BD3C6A495CF6D03A2419BF816" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2994A174464709A26A1A03A2419B9397" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_73A9A4360D29A972E1F903A2419B373A_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2994A174464709A26A1A03A2419B9397" xlink:to="loc_us-gaap_RelatedPartyDomain_73A9A4360D29A972E1F903A2419B373A_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_73A9A4360D29A972E1F903A2419B373A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2994A174464709A26A1A03A2419B9397" xlink:to="loc_us-gaap_RelatedPartyDomain_73A9A4360D29A972E1F903A2419B373A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="loc_us-gaap_AffiliatedEntityMember_F9D19F03E6B14D25CE9803A2419B3CEA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_73A9A4360D29A972E1F903A2419B373A" xlink:to="loc_us-gaap_AffiliatedEntityMember_F9D19F03E6B14D25CE9803A2419B3CEA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_C78C0E89D0DE114BBD6E03A2419B55CA" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_011AC87BD3C6A495CF6D03A2419BF816" xlink:to="loc_us-gaap_CounterpartyNameAxis_C78C0E89D0DE114BBD6E03A2419B55CA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_B228C247730454A4268C03A2419B9875_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_C78C0E89D0DE114BBD6E03A2419B55CA" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_B228C247730454A4268C03A2419B9875_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_B228C247730454A4268C03A2419B9875" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_C78C0E89D0DE114BBD6E03A2419B55CA" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_B228C247730454A4268C03A2419B9875" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_A0414CCF93BEDA47A8AE03A2419B231D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_B228C247730454A4268C03A2419B9875" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_A0414CCF93BEDA47A8AE03A2419B231D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_InterestExpenseRelatedParty" xlink:label="loc_us-gaap_InterestExpenseRelatedParty_D7635423FF5CE3A52B2D03A2419B0D0D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_B2A973D7A7C9278A07A103A2419B3979" xlink:to="loc_us-gaap_InterestExpenseRelatedParty_D7635423FF5CE3A52B2D03A2419B0D0D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_InterestCostsCapitalized" xlink:label="loc_us-gaap_InterestCostsCapitalized_12A1EB9C64578652C21B03A2419BF43A" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_B2A973D7A7C9278A07A103A2419B3979" xlink:to="loc_us-gaap_InterestCostsCapitalized_12A1EB9C64578652C21B03A2419BF43A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_InterestPayableCurrent" xlink:label="loc_us-gaap_InterestPayableCurrent_9B502479B22E3A0D4A6803A2419B44BF" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_B2A973D7A7C9278A07A103A2419B3979" xlink:to="loc_us-gaap_InterestPayableCurrent_9B502479B22E3A0D4A6803A2419B44BF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DueToRelatedPartiesNoncurrent" xlink:label="loc_us-gaap_DueToRelatedPartiesNoncurrent_191588238352ECAB44DC03A2419CAA47" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_B2A973D7A7C9278A07A103A2419B3979" xlink:to="loc_us-gaap_DueToRelatedPartiesNoncurrent_191588238352ECAB44DC03A2419CAA47" 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/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_DFC8C57C9D74A309FBA2C8EB91F17AF4" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_46BE43D6889B8FF5EB72C8EB91EF23B3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_DFC8C57C9D74A309FBA2C8EB91F17AF4" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_46BE43D6889B8FF5EB72C8EB91EF23B3" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_8B2DD7AC880F96CE1566C8EB91F00500" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_46BE43D6889B8FF5EB72C8EB91EF23B3" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_8B2DD7AC880F96CE1566C8EB91F00500" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_7E9FCEA03B8F3FD0B537C8EB91F00680_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_8B2DD7AC880F96CE1566C8EB91F00500" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_7E9FCEA03B8F3FD0B537C8EB91F00680_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_7E9FCEA03B8F3FD0B537C8EB91F00680" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_8B2DD7AC880F96CE1566C8EB91F00500" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_7E9FCEA03B8F3FD0B537C8EB91F00680" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_SiteLeaseAgreementMember" xlink:label="loc_wlkp_SiteLeaseAgreementMember_AB3316B3E143BC3F9B9DC8EB91F0E997" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_7E9FCEA03B8F3FD0B537C8EB91F00680" xlink:to="loc_wlkp_SiteLeaseAgreementMember_AB3316B3E143BC3F9B9DC8EB91F0E997" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_D0469119C91D06EBA74BC8EB91F0B123" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_46BE43D6889B8FF5EB72C8EB91EF23B3" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_D0469119C91D06EBA74BC8EB91F0B123" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_04A000A2B6CFA4DB5909C8EB91F0C4B8_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_D0469119C91D06EBA74BC8EB91F0B123" xlink:to="loc_us-gaap_RelatedPartyDomain_04A000A2B6CFA4DB5909C8EB91F0C4B8_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_04A000A2B6CFA4DB5909C8EB91F0C4B8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_D0469119C91D06EBA74BC8EB91F0B123" xlink:to="loc_us-gaap_RelatedPartyDomain_04A000A2B6CFA4DB5909C8EB91F0C4B8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="loc_us-gaap_AffiliatedEntityMember_4E21ACD4DD0350A47C58C8EB91F0B17E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_04A000A2B6CFA4DB5909C8EB91F0C4B8" xlink:to="loc_us-gaap_AffiliatedEntityMember_4E21ACD4DD0350A47C58C8EB91F0B17E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_9210D18AC0E0635EEDEDC8EB91F06B76" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_46BE43D6889B8FF5EB72C8EB91EF23B3" xlink:to="loc_us-gaap_CounterpartyNameAxis_9210D18AC0E0635EEDEDC8EB91F06B76" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_2966839915177C5DBBA5C8EB91F0DB1E_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_9210D18AC0E0635EEDEDC8EB91F06B76" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_2966839915177C5DBBA5C8EB91F0DB1E_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_2966839915177C5DBBA5C8EB91F0DB1E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_9210D18AC0E0635EEDEDC8EB91F06B76" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_2966839915177C5DBBA5C8EB91F0DB1E" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_1D78B3A768211C918544C8EB91F05D10" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_2966839915177C5DBBA5C8EB91F0DB1E" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_1D78B3A768211C918544C8EB91F05D10" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_B040EE0961B1243C459DC8EB91F0352B" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_46BE43D6889B8FF5EB72C8EB91EF23B3" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_B040EE0961B1243C459DC8EB91F0352B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_37B3F4176693806BCA57C8EB91F04134_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_B040EE0961B1243C459DC8EB91F0352B" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_37B3F4176693806BCA57C8EB91F04134_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_37B3F4176693806BCA57C8EB91F04134" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_B040EE0961B1243C459DC8EB91F0352B" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_37B3F4176693806BCA57C8EB91F04134" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SeniorNotesMember" xlink:label="loc_us-gaap_SeniorNotesMember_A3DDA7833A19B5AADE92C8EB91F01C8F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_37B3F4176693806BCA57C8EB91F04134" xlink:to="loc_us-gaap_SeniorNotesMember_A3DDA7833A19B5AADE92C8EB91F01C8F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="loc_us-gaap_CreditFacilityAxis_0622BBC717EDB44F93F9C8EB91F0F86F" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_46BE43D6889B8FF5EB72C8EB91EF23B3" xlink:to="loc_us-gaap_CreditFacilityAxis_0622BBC717EDB44F93F9C8EB91F0F86F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_BFEABB32C4E9F3A7B689C8EB91F0CC8C_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_0622BBC717EDB44F93F9C8EB91F0F86F" xlink:to="loc_us-gaap_CreditFacilityDomain_BFEABB32C4E9F3A7B689C8EB91F0CC8C_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_BFEABB32C4E9F3A7B689C8EB91F0CC8C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_0622BBC717EDB44F93F9C8EB91F0F86F" xlink:to="loc_us-gaap_CreditFacilityDomain_BFEABB32C4E9F3A7B689C8EB91F0CC8C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_0A1D57F061CDB22CD928C8EB91F005C5" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_BFEABB32C4E9F3A7B689C8EB91F0CC8C" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_0A1D57F061CDB22CD928C8EB91F005C5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_FC3911CA106A36355E29C8EB91F194E7" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_46BE43D6889B8FF5EB72C8EB91EF23B3" xlink:to="loc_dei_LegalEntityAxis_FC3911CA106A36355E29C8EB91F194E7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_AFE3A49F87D6335EB208C8EB91F1ED89_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_FC3911CA106A36355E29C8EB91F194E7" xlink:to="loc_dei_EntityDomain_AFE3A49F87D6335EB208C8EB91F1ED89_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_AFE3A49F87D6335EB208C8EB91F1ED89" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_FC3911CA106A36355E29C8EB91F194E7" xlink:to="loc_dei_EntityDomain_AFE3A49F87D6335EB208C8EB91F1ED89" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_WestlakeChemicalOpCoLPMember" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_3A9B4F86AE1557CF90D2C8EB91F1B083" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_AFE3A49F87D6335EB208C8EB91F1ED89" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_3A9B4F86AE1557CF90D2C8EB91F1B083" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_ABB2698E842F3973423BC8EB91F16C4F" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_AFE3A49F87D6335EB208C8EB91F1ED89" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_ABB2698E842F3973423BC8EB91F16C4F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_33D2087181E5E774630FC8EB91F19946" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_DFC8C57C9D74A309FBA2C8EB91F17AF4" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_33D2087181E5E774630FC8EB91F19946" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongTermDebt" xlink:label="loc_us-gaap_LongTermDebt_033BCEB05E7C46224163C8EB91F199B5" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_DFC8C57C9D74A309FBA2C8EB91F17AF4" xlink:to="loc_us-gaap_LongTermDebt_033BCEB05E7C46224163C8EB91F199B5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscount" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscount_8EF33F9BE24CE5F3C950C8EB91F12238" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_DFC8C57C9D74A309FBA2C8EB91F17AF4" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscount_8EF33F9BE24CE5F3C950C8EB91F12238" 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/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_2213E0148AB4658E24D5B407DB6A965D" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_155ED16FB0C629E2145EB407DB6A8025" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_2213E0148AB4658E24D5B407DB6A965D" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_155ED16FB0C629E2145EB407DB6A8025" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1D49EAE83C7244FBF66BB407DB6A4A7D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_155ED16FB0C629E2145EB407DB6A8025" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1D49EAE83C7244FBF66BB407DB6A4A7D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_B7C07EAD37AC78D263A1B407DB6ACD2A_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1D49EAE83C7244FBF66BB407DB6A4A7D" xlink:to="loc_us-gaap_RelatedPartyDomain_B7C07EAD37AC78D263A1B407DB6ACD2A_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_B7C07EAD37AC78D263A1B407DB6ACD2A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1D49EAE83C7244FBF66BB407DB6A4A7D" xlink:to="loc_us-gaap_RelatedPartyDomain_B7C07EAD37AC78D263A1B407DB6ACD2A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="loc_us-gaap_AffiliatedEntityMember_3D9B79A709B89F3C85B7B407DB6A4547" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_B7C07EAD37AC78D263A1B407DB6ACD2A" xlink:to="loc_us-gaap_AffiliatedEntityMember_3D9B79A709B89F3C85B7B407DB6A4547" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_E6FE60E8B6047FE39FF9B407DB6A1598" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_155ED16FB0C629E2145EB407DB6A8025" xlink:to="loc_us-gaap_CounterpartyNameAxis_E6FE60E8B6047FE39FF9B407DB6A1598" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_93297F9C2485AFD5BF1CB407DB6A42B2_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_E6FE60E8B6047FE39FF9B407DB6A1598" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_93297F9C2485AFD5BF1CB407DB6A42B2_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_93297F9C2485AFD5BF1CB407DB6A42B2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_E6FE60E8B6047FE39FF9B407DB6A1598" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_93297F9C2485AFD5BF1CB407DB6A42B2" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_D69EB64AA77BEA8914D2B407DB6A1508" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_93297F9C2485AFD5BF1CB407DB6A42B2" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_D69EB64AA77BEA8914D2B407DB6A1508" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_RelatedPartyTransactionPurchasesFromRelatedPartyCapitalizedAsAssets" xlink:label="loc_wlkp_RelatedPartyTransactionPurchasesFromRelatedPartyCapitalizedAsAssets_7337EE0EFCE5B78936C3B407DB6AD75B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_2213E0148AB4658E24D5B407DB6A965D" xlink:to="loc_wlkp_RelatedPartyTransactionPurchasesFromRelatedPartyCapitalizedAsAssets_7337EE0EFCE5B78936C3B407DB6AD75B" 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/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_57D6189DD7EEEE547D5FB407DB763E26" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_BB499847C72A3940AE80B407DB75FBA5" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_57D6189DD7EEEE547D5FB407DB763E26" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_BB499847C72A3940AE80B407DB75FBA5" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_D33903647F69F65A063DB407DB751532" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_BB499847C72A3940AE80B407DB75FBA5" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_D33903647F69F65A063DB407DB751532" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_13B5A9CFC8AAD958C711B407DB750F0A_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_D33903647F69F65A063DB407DB751532" xlink:to="loc_us-gaap_RelatedPartyDomain_13B5A9CFC8AAD958C711B407DB750F0A_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_13B5A9CFC8AAD958C711B407DB750F0A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_D33903647F69F65A063DB407DB751532" xlink:to="loc_us-gaap_RelatedPartyDomain_13B5A9CFC8AAD958C711B407DB750F0A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="loc_us-gaap_AffiliatedEntityMember_FFD2838A2CBBE003BF12B407DB765581" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_13B5A9CFC8AAD958C711B407DB750F0A" xlink:to="loc_us-gaap_AffiliatedEntityMember_FFD2838A2CBBE003BF12B407DB765581" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_A5A327C7B558C095B2FCB407DB76FE3F" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_BB499847C72A3940AE80B407DB75FBA5" xlink:to="loc_us-gaap_CounterpartyNameAxis_A5A327C7B558C095B2FCB407DB76FE3F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_FA1660EC8A5A6695D3B3B407DB76C438_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_A5A327C7B558C095B2FCB407DB76FE3F" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_FA1660EC8A5A6695D3B3B407DB76C438_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_FA1660EC8A5A6695D3B3B407DB76C438" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_A5A327C7B558C095B2FCB407DB76FE3F" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_FA1660EC8A5A6695D3B3B407DB76C438" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_91CE87FD1633AFFA2563B407DB76B3F2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_FA1660EC8A5A6695D3B3B407DB76C438" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_91CE87FD1633AFFA2563B407DB76B3F2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RevenueFromRelatedParties" xlink:label="loc_us-gaap_RevenueFromRelatedParties_E51D99DE8E96D970A47CB407DB769209" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_57D6189DD7EEEE547D5FB407DB763E26" xlink:to="loc_us-gaap_RevenueFromRelatedParties_E51D99DE8E96D970A47CB407DB769209" 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/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_81DB82CE6D06DA2DB11EB407DB6E65A9" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_B75AA6B56D02F9B94C7CB407DB6D8B5A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_81DB82CE6D06DA2DB11EB407DB6E65A9" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_B75AA6B56D02F9B94C7CB407DB6D8B5A" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_BF1EDF1CD0FD5AE777CEB407DB6DB564" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_B75AA6B56D02F9B94C7CB407DB6D8B5A" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_BF1EDF1CD0FD5AE777CEB407DB6DB564" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_0C672060F349BE750ABBB407DB6D5D68_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_BF1EDF1CD0FD5AE777CEB407DB6DB564" xlink:to="loc_us-gaap_RelatedPartyDomain_0C672060F349BE750ABBB407DB6D5D68_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_0C672060F349BE750ABBB407DB6D5D68" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_BF1EDF1CD0FD5AE777CEB407DB6DB564" xlink:to="loc_us-gaap_RelatedPartyDomain_0C672060F349BE750ABBB407DB6D5D68" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="loc_us-gaap_AffiliatedEntityMember_297B0EB52DC503E1960BB407DB6D5E86" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_0C672060F349BE750ABBB407DB6D5D68" xlink:to="loc_us-gaap_AffiliatedEntityMember_297B0EB52DC503E1960BB407DB6D5E86" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_C8D5330F0447FCC53409B407DB6DE6CA" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_B75AA6B56D02F9B94C7CB407DB6D8B5A" xlink:to="loc_us-gaap_CounterpartyNameAxis_C8D5330F0447FCC53409B407DB6DE6CA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_723AD11D0E3313FA4175B407DB6DA36F_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_C8D5330F0447FCC53409B407DB6DE6CA" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_723AD11D0E3313FA4175B407DB6DA36F_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_723AD11D0E3313FA4175B407DB6DA36F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_C8D5330F0447FCC53409B407DB6DE6CA" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_723AD11D0E3313FA4175B407DB6DA36F" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_7B56570F580D79CCB7B9B407DB6DCDB8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_723AD11D0E3313FA4175B407DB6DA36F" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_7B56570F580D79CCB7B9B407DB6DCDB8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionSellingGeneralAndAdministrativeExpensesFromTransactionsWithRelatedParty" xlink:label="loc_us-gaap_RelatedPartyTransactionSellingGeneralAndAdministrativeExpensesFromTransactionsWithRelatedParty_6A2894C678A354430D0DB407DB6E740C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_81DB82CE6D06DA2DB11EB407DB6E65A9" xlink:to="loc_us-gaap_RelatedPartyTransactionSellingGeneralAndAdministrativeExpensesFromTransactionsWithRelatedParty_6A2894C678A354430D0DB407DB6E740C" 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/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_4C0AF8431DBB1526F5BBC8ED2B512CB8" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_4B86AE0EA73354EC2BA8C8ED2B50B458" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_4C0AF8431DBB1526F5BBC8ED2B512CB8" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_4B86AE0EA73354EC2BA8C8ED2B50B458" 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_564A74830B3BF637956FC8ED2B9BCB3F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_4B86AE0EA73354EC2BA8C8ED2B50B458" xlink:to="loc_dei_LegalEntityAxis_564A74830B3BF637956FC8ED2B9BCB3F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_7C1C6467BA22B42D03ACC8ED2C51B15B_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_564A74830B3BF637956FC8ED2B9BCB3F" xlink:to="loc_dei_EntityDomain_7C1C6467BA22B42D03ACC8ED2C51B15B_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_7C1C6467BA22B42D03ACC8ED2C51B15B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_564A74830B3BF637956FC8ED2B9BCB3F" xlink:to="loc_dei_EntityDomain_7C1C6467BA22B42D03ACC8ED2C51B15B" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_WestlakeChemicalOpCoLPMember" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_5A817A37656E8CA47E34C8ED2BB87511" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7C1C6467BA22B42D03ACC8ED2C51B15B" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_5A817A37656E8CA47E34C8ED2BB87511" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_A7705665B7B09E477028C8ED2B5199D1" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_4B86AE0EA73354EC2BA8C8ED2B50B458" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_A7705665B7B09E477028C8ED2B5199D1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_E99D2EB594212308917AC8ED2B51F30A_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_A7705665B7B09E477028C8ED2B5199D1" xlink:to="loc_us-gaap_RelatedPartyDomain_E99D2EB594212308917AC8ED2B51F30A_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_E99D2EB594212308917AC8ED2B51F30A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_A7705665B7B09E477028C8ED2B5199D1" xlink:to="loc_us-gaap_RelatedPartyDomain_E99D2EB594212308917AC8ED2B51F30A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="loc_us-gaap_AffiliatedEntityMember_CBBCA5B84EE70C0013BCC8ED2BA593A8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_E99D2EB594212308917AC8ED2B51F30A" xlink:to="loc_us-gaap_AffiliatedEntityMember_CBBCA5B84EE70C0013BCC8ED2BA593A8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_26B81FDAE5E057FB55D7C8ED2B51E25E" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_4B86AE0EA73354EC2BA8C8ED2B50B458" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_26B81FDAE5E057FB55D7C8ED2B51E25E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_DB68A285AF78249FCF6EC8ED2B51A684_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_26B81FDAE5E057FB55D7C8ED2B51E25E" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_DB68A285AF78249FCF6EC8ED2B51A684_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_DB68A285AF78249FCF6EC8ED2B51A684" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_26B81FDAE5E057FB55D7C8ED2B51E25E" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_DB68A285AF78249FCF6EC8ED2B51A684" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_SiteLeaseAgreementMember" xlink:label="loc_wlkp_SiteLeaseAgreementMember_DFA20FFB4E21CBC73C57C8ED2BAE8025" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_DB68A285AF78249FCF6EC8ED2B51A684" xlink:to="loc_wlkp_SiteLeaseAgreementMember_DFA20FFB4E21CBC73C57C8ED2BAE8025" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_LesseeLeasingArrangementsOperatingLeasesNumber" xlink:label="loc_wlkp_LesseeLeasingArrangementsOperatingLeasesNumber_620CD523D6F4D8A81B30C8ED2B917576" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_4C0AF8431DBB1526F5BBC8ED2B512CB8" xlink:to="loc_wlkp_LesseeLeasingArrangementsOperatingLeasesNumber_620CD523D6F4D8A81B30C8ED2B917576" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LesseeLeasingArrangementsOperatingLeasesTermOfContract" xlink:label="loc_us-gaap_LesseeLeasingArrangementsOperatingLeasesTermOfContract_71D32F7C09BC80A6AFACC8EDEA4D98EC" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_4C0AF8431DBB1526F5BBC8ED2B512CB8" xlink:to="loc_us-gaap_LesseeLeasingArrangementsOperatingLeasesTermOfContract_71D32F7C09BC80A6AFACC8EDEA4D98EC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LeaseAndRentalExpense" xlink:label="loc_us-gaap_LeaseAndRentalExpense_F120C92683CB6CACC0EEC8ED96C05CF1" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_4C0AF8431DBB1526F5BBC8ED2B512CB8" xlink:to="loc_us-gaap_LeaseAndRentalExpense_F120C92683CB6CACC0EEC8ED96C05CF1" 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/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SubsequentEventLineItems" xlink:label="loc_us-gaap_SubsequentEventLineItems_21F6D70F72B63121FDE6B74E6AADF9CC" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SubsequentEventTable" xlink:label="loc_us-gaap_SubsequentEventTable_F5F9FC532076E9DED29FB74E6AA7F918" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_21F6D70F72B63121FDE6B74E6AADF9CC" xlink:to="loc_us-gaap_SubsequentEventTable_F5F9FC532076E9DED29FB74E6AA7F918" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_928F4262326BAB95CEA0B74E6AA78462" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_F5F9FC532076E9DED29FB74E6AA7F918" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_928F4262326BAB95CEA0B74E6AA78462" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_E94961B9A18A7FCDAF67B74E6AA76839_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_928F4262326BAB95CEA0B74E6AA78462" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_E94961B9A18A7FCDAF67B74E6AA76839_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_E94961B9A18A7FCDAF67B74E6AA76839" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_928F4262326BAB95CEA0B74E6AA78462" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_E94961B9A18A7FCDAF67B74E6AA76839" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaap_SubsequentEventMember_4B7C4ECB6C1281FA1348B785B677CE3A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_E94961B9A18A7FCDAF67B74E6AA76839" xlink:to="loc_us-gaap_SubsequentEventMember_4B7C4ECB6C1281FA1348B785B677CE3A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_D7589949CC5DD6C3ACE5B74E6AAC00AB" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_F5F9FC532076E9DED29FB74E6AA7F918" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_D7589949CC5DD6C3ACE5B74E6AAC00AB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_00225A1890197EB62145B74E6AAC7B30_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_D7589949CC5DD6C3ACE5B74E6AAC00AB" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_00225A1890197EB62145B74E6AAC7B30_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_00225A1890197EB62145B74E6AAC7B30" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_D7589949CC5DD6C3ACE5B74E6AAC00AB" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_00225A1890197EB62145B74E6AAC7B30" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_WestlakeChemicalOpCoLPMember" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_E2318C79C8DD0B44D711B74E6AAD5B3D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_00225A1890197EB62145B74E6AAC7B30" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_E2318C79C8DD0B44D711B74E6AAD5B3D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit" xlink:label="loc_us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit_A168BEA49AEB0036D0D7B74E6AAD0493" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_21F6D70F72B63121FDE6B74E6AADF9CC" xlink:to="loc_us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit_A168BEA49AEB0036D0D7B74E6AAD0493" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DistributionMadeToLimitedPartnerCashDistributionsDeclared" xlink:label="loc_us-gaap_DistributionMadeToLimitedPartnerCashDistributionsDeclared_040E844115FF8F2E2034B74E6AADFD11" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_21F6D70F72B63121FDE6B74E6AADF9CC" xlink:to="loc_us-gaap_DistributionMadeToLimitedPartnerCashDistributionsDeclared_040E844115FF8F2E2034B74E6AADFD11" 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">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_66BF4294510342E20015B407DB252352" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_0C06E9401C23D55D5B04B407DB2477F6" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_66BF4294510342E20015B407DB252352" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_0C06E9401C23D55D5B04B407DB2477F6" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_37E6252AD896A19190F7B407DB24547F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_0C06E9401C23D55D5B04B407DB2477F6" xlink:to="loc_us-gaap_CounterpartyNameAxis_37E6252AD896A19190F7B407DB24547F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_31AFC3F130C19F6043A1B407DB24B7DC_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_37E6252AD896A19190F7B407DB24547F" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_31AFC3F130C19F6043A1B407DB24B7DC_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_31AFC3F130C19F6043A1B407DB24B7DC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_37E6252AD896A19190F7B407DB24547F" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_31AFC3F130C19F6043A1B407DB24B7DC" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_2486B54D36B7CECB9CC9B407DB2403BA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_31AFC3F130C19F6043A1B407DB24B7DC" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_2486B54D36B7CECB9CC9B407DB2403BA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_A9C4522DB3D77BF3A0A3B407DB25B157" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_0C06E9401C23D55D5B04B407DB2477F6" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_A9C4522DB3D77BF3A0A3B407DB25B157" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_151870DFF5322F5B1D2CB407DB25EAA7_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_A9C4522DB3D77BF3A0A3B407DB25B157" xlink:to="loc_us-gaap_RelatedPartyDomain_151870DFF5322F5B1D2CB407DB25EAA7_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_151870DFF5322F5B1D2CB407DB25EAA7" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_A9C4522DB3D77BF3A0A3B407DB25B157" xlink:to="loc_us-gaap_RelatedPartyDomain_151870DFF5322F5B1D2CB407DB25EAA7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="loc_us-gaap_AffiliatedEntityMember_FA78FE5F79BD9626342BB407DB2571EA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_151870DFF5322F5B1D2CB407DB25EAA7" xlink:to="loc_us-gaap_AffiliatedEntityMember_FA78FE5F79BD9626342BB407DB2571EA" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_InterestIncurredAddedtoDebtOutstanding" xlink:label="loc_wlkp_InterestIncurredAddedtoDebtOutstanding_3482B96794524192B668B407DB251008" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_66BF4294510342E20015B407DB252352" xlink:to="loc_wlkp_InterestIncurredAddedtoDebtOutstanding_3482B96794524192B668B407DB251008" xlink:type="arc" />
    <loc xlink:href="wlkp-20150930.xsd#wlkp_IncreaseDecreaseinCapitalExpenditureAccrual" xlink:label="loc_wlkp_IncreaseDecreaseinCapitalExpenditureAccrual_7BF2124FCDE499AF24D7B407DB25C90A" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_66BF4294510342E20015B407DB252352" xlink:to="loc_wlkp_IncreaseDecreaseinCapitalExpenditureAccrual_7BF2124FCDE499AF24D7B407DB25C90A" xlink:type="arc" />
  </definitionLink>
</linkbase>
