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      <filer>
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          <ccc>XXXXXXXX</ccc>
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      <seriesClassInfo>
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        <classId>C000051437</classId>
        <classId>C000067780</classId>
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    </filerInfo>
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      <regFileNumber>811-02224</regFileNumber>
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      <regLei>VQ1HG47DNRJG3HBJH467</regLei>
      <regStreet1>1295 State Street</regStreet1>
      <regCity>Springfield</regCity>
      <regStateConditional regCountry="US" regState="US-MA"/>
      <regZipOrPostalCode>01111-0001</regZipOrPostalCode>
      <regPhone>413-744-1000</regPhone>
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      <seriesId>S000018541</seriesId>
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      <repPdEnd>2026-12-31</repPdEnd>
      <repPdDate>2026-06-30</repPdDate>
      <isFinalFiling>N</isFinalFiling>
    </genInfo>
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      <totLiabs>674377.51</totLiabs>
      <netAssets>850137205.54</netAssets>
      <assetsAttrMiscSec>0.00000000</assetsAttrMiscSec>
      <assetsInvested>0.00000000</assetsInvested>
      <amtPayOneYrBanksBorr>0.00000000</amtPayOneYrBanksBorr>
      <amtPayOneYrCtrldComp>0.00000000</amtPayOneYrCtrldComp>
      <amtPayOneYrOthAffil>0.00000000</amtPayOneYrOthAffil>
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      <liquidPref>0.00000000</liquidPref>
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        <monthlyTotReturns>
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        <title>Invesco Global Strategic Income Fund</title>
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        <fairValLevel>1</fairValLevel>
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        <fairValLevel>1</fairValLevel>
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        <fairValLevel>1</fairValLevel>
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        <fairValLevel>1</fairValLevel>
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        <fairValLevel>1</fairValLevel>
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        <fairValLevel>1</fairValLevel>
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        <name>MML SMALL COMPANY VALUE FUND</name>
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        <fairValLevel>1</fairValLevel>
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        <curCd>USD</curCd>
        <valUSD>7044280.91000000</valUSD>
        <pctVal>0.828605178563</pctVal>
        <payoffProfile>Long</payoffProfile>
        <assetCat>EC</assetCat>
        <issuerCat>RF</issuerCat>
        <invCountry>US</invCountry>
        <isRestrictedSec>N</isRestrictedSec>
        
        <fairValLevel>1</fairValLevel>
        <securityLending>
          <isCashCollateral>N</isCashCollateral>
          <isNonCashCollateral>N</isNonCashCollateral>
          <isLoanByFund>N</isLoanByFund>
        </securityLending>
      </invstOrSec>
      <invstOrSec>
        <name>MML SHORT DURATION BOND FUND</name>
        <lei>XL07OZJZFFLZ255H7071</lei>
        <title>MML SHORT DURATION BOND FUND</title>
        <cusip>55312G754</cusip>
        <identifiers>
          <isin value="US55312G7549"/>
        </identifiers>
        <balance>2907276.82000000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>27153965.48000000</valUSD>
        <pctVal>3.194068593051</pctVal>
        <payoffProfile>Long</payoffProfile>
        <assetCat>EC</assetCat>
        <issuerCat>RF</issuerCat>
        <invCountry>US</invCountry>
        <isRestrictedSec>N</isRestrictedSec>
        
        <fairValLevel>1</fairValLevel>
        <securityLending>
          <isCashCollateral>N</isCashCollateral>
          <isNonCashCollateral>N</isNonCashCollateral>
          <isLoanByFund>N</isLoanByFund>
        </securityLending>
      </invstOrSec>
      <invstOrSec>
        <name>MML Barings High Yield Fund</name>
        <lei>AQDRLVGKF0IT8SWIC757</lei>
        <title>MML Barings High Yield Fund</title>
        <cusip>57629H327</cusip>
        <identifiers>
          <isin value="US57629H3277"/>
        </identifiers>
        <balance>246370.66000000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>1998066.07000000</valUSD>
        <pctVal>0.235028658548</pctVal>
        <payoffProfile>Long</payoffProfile>
        <assetCat>EC</assetCat>
        <issuerCat>RF</issuerCat>
        <invCountry>US</invCountry>
        <isRestrictedSec>N</isRestrictedSec>
        
        <fairValLevel>1</fairValLevel>
        <securityLending>
          <isCashCollateral>N</isCashCollateral>
          <isNonCashCollateral>N</isNonCashCollateral>
          <isLoanByFund>N</isLoanByFund>
        </securityLending>
      </invstOrSec>
      <invstOrSec>
        <name>PIMCO Variable Insurance Trust - Long-Term U.S. Government Portfolio</name>
        <lei>1HF6TMDVSLQTVB8TF611</lei>
        <title>PIMCO Variable Insurance Trust - Long-Term U.S. Government Portfolio</title>
        <cusip>693394710</cusip>
        <identifiers>
          <isin value="US6933947102"/>
        </identifiers>
        <balance>1545941.88000000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>11409051.10000000</valUSD>
        <pctVal>1.342024678563</pctVal>
        <payoffProfile>Long</payoffProfile>
        <assetCat>EC</assetCat>
        <issuerCat>RF</issuerCat>
        <invCountry>US</invCountry>
        <isRestrictedSec>N</isRestrictedSec>
        
        <fairValLevel>1</fairValLevel>
        <securityLending>
          <isCashCollateral>N</isCashCollateral>
          <isNonCashCollateral>N</isNonCashCollateral>
          <isLoanByFund>N</isLoanByFund>
        </securityLending>
      </invstOrSec>
      <invstOrSec>
        <name>Fidelity VIP Emerging Markets Portfolio</name>
        <lei>N/A</lei>
        <title>Fidelity VIP Emerging Markets Portfolio</title>
        <cusip>922177324</cusip>
        <identifiers>
          <isin value="US9221773248"/>
        </identifiers>
        <balance>805445.25000000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>16197504.04000000</valUSD>
        <pctVal>1.905281163375</pctVal>
        <payoffProfile>Long</payoffProfile>
        <assetCat>EC</assetCat>
        <issuerCat>RF</issuerCat>
        <invCountry>US</invCountry>
        <isRestrictedSec>N</isRestrictedSec>
        
        <fairValLevel>1</fairValLevel>
        <securityLending>
          <isCashCollateral>N</isCashCollateral>
          <isNonCashCollateral>N</isNonCashCollateral>
          <isLoanByFund>N</isLoanByFund>
        </securityLending>
      </invstOrSec>
    </invstOrSecs>
    <explntrNotes>
      <explntrNote note="Monthly returns presented in Item B.5(a) have been calculated without deducting any applicable sales loads or redemption fees." noteItem="B.5.a"/>
    </explntrNotes>
    <signature>
      <ncom:dateSigned>2026-07-15</ncom:dateSigned>
      <ncom:nameOfApplicant>MML SERIES INVESTMENT FUND</ncom:nameOfApplicant>
      <ncom:signature>Renee Hitchcock</ncom:signature>
      <ncom:signerName>Renee Hitchcock</ncom:signerName>
      <ncom:title>CFO and Treasurer</ncom:title>
    </signature>
  </formData>
</edgarSubmission>
