<?xml version="1.0" encoding="us-ascii"?>
<!-- DFIN ActiveDisclosure(SM) XBRL Schema Document - http://www.dfinsolutions.com/ -->
<!-- Creation Date      : 2021-03-04T19:27:06.6612451+00:00 -->
<!-- Version            : 5.0.1.571 -->
<!-- Package ID         : 7e9294712295487d94fbeb8c086ebad6 -->
<!-- Copyright (c) 2021 Donnelley Financial Solutions, Inc. All Rights Reserved. -->
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  <xsd:element id="smlp_LiabilityManagementTransactionsTextBlock" name="LiabilityManagementTransactionsTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_LiabilityManagementTransactionsAbstract" name="LiabilityManagementTransactionsAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_LeasesCommitmentsAndContingenciesDisclosureTextBlock" name="LeasesCommitmentsAndContingenciesDisclosureTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_IntangibleAssetsandNoncurrentLiabilitiesPolicyPolicyTextBlock" name="IntangibleAssetsandNoncurrentLiabilitiesPolicyPolicyTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_ScheduleOfPropertyPlantAndEquipmentUsefulLifeTableTextBlock" name="ScheduleOfPropertyPlantAndEquipmentUsefulLifeTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_ScheduleOfContractWithCustomerAssetTableTextBlock" name="ScheduleOfContractWithCustomerAssetTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_ScheduleOfDepreciationExpenseAndCapitalizedInterestCostsTableTextBlock" name="ScheduleOfDepreciationExpenseAndCapitalizedInterestCostsTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_ScheduleOfRecognizedAmortizationIncomeExpenseTableTextBlock" name="ScheduleOfRecognizedAmortizationIncomeExpenseTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_ScheduleOfPartnerUnitsActivityTableTextBlock" name="ScheduleOfPartnerUnitsActivityTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_LeaseAssetsAndLiabilitiesTableTextBlock" name="LeaseAssetsAndLiabilitiesTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_ScheduleOfFutureMinimumRentalPaymentsForFinanceAndOperatingLeasesAndSubleaseIncomeTableTextBlock" name="ScheduleOfFutureMinimumRentalPaymentsForFinanceAndOperatingLeasesAndSubleaseIncomeTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_ReconciliationOfNetIncomeToAdjustedEBITDATableTextBlock" name="ReconciliationOfNetIncomeToAdjustedEBITDATableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_CommonUnitsPledgedAsCollateral" name="CommonUnitsPledgedAsCollateral" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xsd:element id="smlp_CommonUnitsNotPledgedAsCollateral" name="CommonUnitsNotPledgedAsCollateral" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xsd:element id="smlp_PurchaseAgreementDate" name="PurchaseAgreementDate" type="xbrli:dateItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_OrganizationAndBusinessOperationsLineItems" name="OrganizationAndBusinessOperationsLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_OrganizationAndBusinessOperationsTable" name="OrganizationAndBusinessOperationsTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_SummitMidstreamPartnersHoldingsLLCMember" name="SummitMidstreamPartnersHoldingsLLCMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_SummitInvestmentsMember" name="SummitInvestmentsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_EnergyCapitalPartnersMember" name="EnergyCapitalPartnersMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_SummitMidstreamGPLLCMember" name="SummitMidstreamGPLLCMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_ReverseUnitSplitMember" name="ReverseUnitSplitMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_ReverseUnitSplit" name="ReverseUnitSplit" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_ReverseUnitSplitExchangeRatio" name="ReverseUnitSplitExchangeRatio" type="xbrli:pureItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_SummaryOfSignificantAccountingPoliciesLineItems" name="SummaryOfSignificantAccountingPoliciesLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_SummaryOfSignificantAccountingPoliciesTable" name="SummaryOfSignificantAccountingPoliciesTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_FavorableGasGatheringContractMember" name="FavorableGasGatheringContractMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_OtherGasGatheringContractMember" name="OtherGasGatheringContractMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_RightsOfWayMember" name="RightsOfWayMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_RevenueFromContractWithCustomerLineItems" name="RevenueFromContractWithCustomerLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_RevenueFromContractWithCustomerTable" name="RevenueFromContractWithCustomerTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_GatheringServicesAndRelatedFeesMember" name="GatheringServicesAndRelatedFeesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_NaturalGasNGLAndCondensateSalesMember" name="NaturalGasNGLAndCondensateSalesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_OtherProductsAndServicesMember" name="OtherProductsAndServicesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_UticaShaleSegmentMember" name="UticaShaleSegmentMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_WillistonBasinSegmentMember" name="WillistonBasinSegmentMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_DJBasinSegmentMember" name="DJBasinSegmentMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_PermianBasinSegmentMember" name="PermianBasinSegmentMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_PiceanceBasinSegmentMember" name="PiceanceBasinSegmentMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_BarnettShaleSegmentMember" name="BarnettShaleSegmentMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_MarcellusShaleSegmentMember" name="MarcellusShaleSegmentMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_ContractWithCustomerAssetAdditions" name="ContractWithCustomerAssetAdditions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smlp_LandandLineFillMember" name="LandandLineFillMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_ImpairmentOfPropertyPlantAndEquipment" name="ImpairmentOfPropertyPlantAndEquipment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smlp_FixedAssetsMember" name="FixedAssetsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_ContractIntangiblesMember" name="ContractIntangiblesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_OtherRevenueMember" name="OtherRevenueMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_CostsAndExpensesMember" name="CostsAndExpensesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_MountaineerMidstreamMember" name="MountaineerMidstreamMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_CapitalizedLegalCost" name="CapitalizedLegalCost" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smlp_JVPartnerMember" name="JVPartnerMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_OhioGatheringCompanyLLCMember" name="OhioGatheringCompanyLLCMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_SummitMidstreamPartnersLLCMember" name="SummitMidstreamPartnersLLCMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_WeightedAverageDiscountRatePercent1" name="WeightedAverageDiscountRatePercent1" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_EquityMethodInvestmentAmortizationofDifferenceBetweenCarryingAmountandUnderlyingEquity" name="EquityMethodInvestmentAmortizationofDifferenceBetweenCarryingAmountandUnderlyingEquity" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smlp_EquityMethodInvestmentRollForward" name="EquityMethodInvestmentRollForward" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_OhioCondensateCompanyLLCMember" name="OhioCondensateCompanyLLCMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_OhioCondensateCompanyMember" name="OhioCondensateCompanyMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_ContractWithCustomerLiabilityCurrentAdditions" name="ContractWithCustomerLiabilityCurrentAdditions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smlp_ContractWithCustomerLiabilityCurrentRevenueRecognized" name="ContractWithCustomerLiabilityCurrentRevenueRecognized" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smlp_ContractWithCustomerLiabilityNoncurrentAdditions" name="ContractWithCustomerLiabilityNoncurrentAdditions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smlp_ContractWithCustomerLiabilityNoncurrentReclassificationToCurrent" name="ContractWithCustomerLiabilityNoncurrentReclassificationToCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smlp_SeniorNotesDueMayTwentyTwentyTwoMember" name="SeniorNotesDueMayTwentyTwentyTwoMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_SeniorSecuredTermLoanFullPaidAugustTwentyTwentyMember" name="SeniorSecuredTermLoanFullPaidAugustTwentyTwentyMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_SeniorNotesDueAprilTwentyTwentyFiveMember" name="SeniorNotesDueAprilTwentyTwentyFiveMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_SeniorNotesDueAugustTwentyTwentyTwoMember" name="SeniorNotesDueAugustTwentyTwentyTwoMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_LineOfCreditFacilityMaturityDateMonthAndYear" name="LineOfCreditFacilityMaturityDateMonthAndYear" type="xbrli:gYearMonthItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_AlternateBaseRateMember" name="AlternateBaseRateMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_LineOfCreditFacilityAccordionFeatureIncreaseLimit" name="LineOfCreditFacilityAccordionFeatureIncreaseLimit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smlp_DebtCovenantRatioOfIndebtednessToNetCapitalSeniorSecured" name="DebtCovenantRatioOfIndebtednessToNetCapitalSeniorSecured" type="xbrli:pureItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xsd:element id="smlp_SeniorSecuredCreditFacilityMaximumLeverageRatio" name="SeniorSecuredCreditFacilityMaximumLeverageRatio" type="xbrli:pureItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xsd:element id="smlp_LeverageRatio" name="LeverageRatio" type="xbrli:pureItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xsd:element id="smlp_CumulativePaymentObligationsMaximum" name="CumulativePaymentObligationsMaximum" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smlp_RatioOfConsolidatedTrailing12monthEBITDAToNetInterestExpense" name="RatioOfConsolidatedTrailing12monthEBITDAToNetInterestExpense" type="xbrli:pureItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xsd:element id="smlp_RatioOfNetIndebtednessToConsolidatedTrailing12MonthEBITDA" name="RatioOfNetIndebtednessToConsolidatedTrailing12MonthEBITDA" type="xbrli:pureItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xsd:element id="smlp_RatioOfFirstLienNetIndebtednessToConsolidatedTrailing12MonthEBITDA" name="RatioOfFirstLienNetIndebtednessToConsolidatedTrailing12MonthEBITDA" type="xbrli:pureItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xsd:element id="smlp_DebtInstrumentPrincipalAmount" name="DebtInstrumentPrincipalAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smlp_AccruedInterestOnLoan" name="AccruedInterestOnLoan" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smlp_ECPNewCoTermLoanCreditAgreementMember" name="ECPNewCoTermLoanCreditAgreementMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_ECPTermLoanCreditAgreementsMember" name="ECPTermLoanCreditAgreementsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_SummitHoldingsAndFinanceCorporationMember" name="SummitHoldingsAndFinanceCorporationMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_TwoThousandTwentyTwoSeniorNotesMember" name="TwoThousandTwentyTwoSeniorNotesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_TwoThousandTwentyFiveSeniorNotesMember" name="TwoThousandTwentyFiveSeniorNotesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_TermLoanResultInConsensualDebtDischargeOfFullAmountOwedInTermLoanExchange" name="TermLoanResultInConsensualDebtDischargeOfFullAmountOwedInTermLoanExchange" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smlp_LiabilityManagementTransactionsMember" name="LiabilityManagementTransactionsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_SMPHTermLoanRestructuringMember" name="SMPHTermLoanRestructuringMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_ABRMember" name="ABRMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_CashPaymentOnDeferredPurchasePriceObligation" name="CashPaymentOnDeferredPurchasePriceObligation" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smlp_SeniorNotesDue2022Member" name="SeniorNotesDue2022Member" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_OpenMarketRepurchasesAndTenderOfferRepurchaseMember" name="OpenMarketRepurchasesAndTenderOfferRepurchaseMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_GainLossOnFaceValueOfSeniorNotes" name="GainLossOnFaceValueOfSeniorNotes" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smlp_DebtTransactionCost" name="DebtTransactionCost" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smlp_SeniorNotesDueTwentyTwentyTwoMember" name="SeniorNotesDueTwentyTwentyTwoMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_SeniorNotesDueTwentyTwentyFiveMember" name="SeniorNotesDueTwentyTwentyFiveMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_ECPLoanRepaymentMember" name="ECPLoanRepaymentMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_TLRestructuringMember" name="TLRestructuringMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_LossContingencyPollutionLiabilityInsurancePolicyCoverage" name="LossContingencyPollutionLiabilityInsurancePolicyCoverage" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smlp_LossContingencyPropertyAndBusinessInterruptionInsurancePolicyCoverage" name="LossContingencyPropertyAndBusinessInterruptionInsurancePolicyCoverage" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smlp_MeadowlarkMidstreamGatheringSystemMember" name="MeadowlarkMidstreamGatheringSystemMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_NumberOfTopCustomers" name="NumberOfTopCustomers" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_FiveLargestCustomersMember" name="FiveLargestCustomersMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_SummitMidstreamHoldingsLLCMember" name="SummitMidstreamHoldingsLLCMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_SeniorNotesDue2025Member" name="SeniorNotesDue2025Member" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_PartnersCapitalLineItems" name="PartnersCapitalLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_PartnersCapitalTable" name="PartnersCapitalTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_SummitMidstreamPartnersLPMember" name="SummitMidstreamPartnersLPMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_PreferredStockExchangeOfferMember" name="PreferredStockExchangeOfferMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_PreferredStockTenderOfferMember" name="PreferredStockTenderOfferMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_DoubleEPipelineLLCMember" name="DoubleEPipelineLLCMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_PermianHoldcoMember" name="PermianHoldcoMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_ECPHoldingsWarrantMember" name="ECPHoldingsWarrantMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_PartnersCapitalAccountUnits2019Activity" name="PartnersCapitalAccountUnits2019Activity" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_PartnersCapitalUnitsTermLoanRestructuring" name="PartnersCapitalUnitsTermLoanRestructuring" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_PreferredUnitExchange" name="PreferredUnitExchange" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_PartnersCapitalAccountUnitsOther" name="PartnersCapitalAccountUnitsOther" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_LimitedPartnerCommonUnitsMember" name="LimitedPartnerCommonUnitsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_AdvisoryFeesAndOtherDirectCosts" name="AdvisoryFeesAndOtherDirectCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smlp_FairValueOfWarrants" name="FairValueOfWarrants" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smlp_DistributionPercentageOfLiquidationPreferenceRate" name="DistributionPercentageOfLiquidationPreferenceRate" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_DistributionPercentageOfLiquidationPreferenceRateDescription" name="DistributionPercentageOfLiquidationPreferenceRateDescription" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_PreferredUnitTender" name="PreferredUnitTender" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_StockPurchasedDuringPeriodShares" name="StockPurchasedDuringPeriodShares" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_StockPurchasedDuringPeriodValue" name="StockPurchasedDuringPeriodValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smlp_PurchasePricePerShare" name="PurchasePricePerShare" type="num:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_PercentageOfSubsidiaryUnits" name="PercentageOfSubsidiaryUnits" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_PercentageOfUndrawnCommitmentUnits" name="PercentageOfUndrawnCommitmentUnits" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_DateUptoWhichWarrantsAreExercisable" name="DateUptoWhichWarrantsAreExercisable" type="xbrli:dateItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_DistributionOfAllAvailableCashMaximumPeriodFollowingEndOfQuarter" name="DistributionOfAllAvailableCashMaximumPeriodFollowingEndOfQuarter" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_PartnersCapitalAccountDeemedContributionFromPreferredTenderOffer" name="PartnersCapitalAccountDeemedContributionFromPreferredTenderOffer" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smlp_LimitedPartnerInterestBeforeSubordinatedUnitsConvertedToCommonUnitsMember" name="LimitedPartnerInterestBeforeSubordinatedUnitsConvertedToCommonUnitsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_WarrantIssuanceForGPBuyInTransaction" name="WarrantIssuanceForGPBuyInTransaction" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smlp_NonCashOrPartNonCashRightOfUseOfAssets" name="NonCashOrPartNonCashRightOfUseOfAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smlp_FairValueOfEquityForTLRestructuring" name="FairValueOfEquityForTLRestructuring" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smlp_LongTermIncentivePlanMember" name="LongTermIncentivePlanMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_OfficeSpaceMember" name="OfficeSpaceMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_MaximumAmountOfFinanceAndOperatingLeaseObligations" name="MaximumAmountOfFinanceAndOperatingLeaseObligations" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smlp_IncrementalBorrowingRate" name="IncrementalBorrowingRate" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_FinanceAndOperatingLeaseRightOfUseAsset" name="FinanceAndOperatingLeaseRightOfUseAsset" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smlp_LeaseLiabilitiesCurrentAbstract" name="LeaseLiabilitiesCurrentAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_FinanceAndOperatingLeaseLiabilityCurrent" name="FinanceAndOperatingLeaseLiabilityCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smlp_LeaseLiabilitiesNoncurrentAbstract" name="LeaseLiabilitiesNoncurrentAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_FinanceAndOperatingLeaseLiabilityNoncurrent" name="FinanceAndOperatingLeaseLiabilityNoncurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smlp_FinanceLeaseCostsAbstract" name="FinanceLeaseCostsAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smlp_LesseeOperatingLeaseLiabilityPaymentsDueYearSix" name="LesseeOperatingLeaseLiabilityPaymentsDueYearSix" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smlp_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearSix" name="LesseeOperatingLeaseLiabilityPaymentsDueAfterYearSix" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smlp_FinanceLeaseLiabilityPaymentsDueYearSix" name="FinanceLeaseLiabilityPaymentsDueYearSix" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smlp_FinanceLeaseLiabilityPaymentsDueAfterYearSix" name="FinanceLeaseLiabilityPaymentsDueAfterYearSix" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smlp_RedRockGatheringCompanyLLCMember" name="RedRockGatheringCompanyLLCMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_PurchaseAndSaleAgreementMember" name="PurchaseAndSaleAgreementMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_TiogaMidstreamLLCMember" name="TiogaMidstreamLLCMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_TwoThousandTwentyRestructuringActivitiesMember" name="TwoThousandTwentyRestructuringActivitiesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_TwoThousandNineteenRestructuringActivitiesMember" name="TwoThousandNineteenRestructuringActivitiesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_OhioGatheringSegmentMember" name="OhioGatheringSegmentMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_CounterpartyAMember" name="CounterpartyAMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_CounterpartyBMember" name="CounterpartyBMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_CounterpartyCMember" name="CounterpartyCMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_CounterpartyCMemberPermianBasinMember" name="CounterpartyCMemberPermianBasinMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_CounterpartyCMemberBarnettShaleMember" name="CounterpartyCMemberBarnettShaleMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_SalesTaxReimbursements" name="SalesTaxReimbursements" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smlp_LetterOfCredit" name="LetterOfCredit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smlp_TermLoanCreditFacilityMember" name="TermLoanCreditFacilityMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smlp_WorkingCapitalCreditFacilityMember" name="WorkingCapitalCreditFacilityMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
</xsd:schema>
