content: <?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/ownership" xmlns:com="http://www.sec.gov/edgar/common">
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    <headerData>
      <submissionType>144</submissionType>
      <filerInfo>
        <filer>
          <filerCredentials>
            <cik>0001227348</cik>
            <ccc>XXXXXXXX</ccc>
          </filerCredentials>
        </filer>
        <liveTestFlag>LIVE</liveTestFlag>
  
  
  
      </filerInfo>
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    <formData>
      <issuerInfo>
        <issuerCik>0001288847</issuerCik>
        <issuerName>Five9, Inc.</issuerName>
        <secFileNumber>001-36383</secFileNumber>
        <issuerAddress>
          <com:street1>3001 Bishop Drive, Suite 350</com:street1>
          <com:city>San Ramon</com:city>
          <com:stateOrCountry>CA</com:stateOrCountry>
          <com:zipCode>94583</com:zipCode>
        </issuerAddress>
        <issuerContactPhone>925-201-2000</issuerContactPhone>
        <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>Barry Zwarenstein</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
        <relationshipsToIssuer>
          <relationshipToIssuer>Officer</relationshipToIssuer>
        </relationshipsToIssuer>
      </issuerInfo>
      <securitiesInformation>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <brokerOrMarketmakerDetails>
          <name>JP Morgan Securities LLC</name>
          <address>
            <com:street1>390 Madison Avenue</com:street1>
            <com:street2>6th Floor</com:street2>
            <com:city>New York</com:city>
            <com:stateOrCountry>NY</com:stateOrCountry>
            <com:zipCode>10017</com:zipCode>
          </address>
        </brokerOrMarketmakerDetails>
        <noOfUnitsSold>25000</noOfUnitsSold>
        <aggregateMarketValue>2159500</aggregateMarketValue>
        <noOfUnitsOutstanding>71176473</noOfUnitsOutstanding>
        <approxSaleDate>07/13/2023</approxSaleDate>
        <securitiesExchangeName>NASDAQ</securitiesExchangeName>
      </securitiesInformation>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>07/13/2023</acquiredDate>
        <natureOfAcquisitionTransaction>Stock Option Exercise</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>25000</amountOfSecuritiesAcquired>
        <paymentDate>07/13/2023</paymentDate>
        <natureOfPayment>Cash</natureOfPayment>
      </securitiesToBeSold>
      <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
      <securitiesSoldInPast3Months>
        <sellerDetails>
          <name>Barry Zwarenstein and Mahbobeh Hirmand Trust</name>
          <address>
            <com:street1>C/o Five9, Inc.</com:street1>
            <com:street2>3001 Bishop Drive, Suite 350</com:street2>
            <com:city>San Ramon</com:city>
            <com:stateOrCountry>CA</com:stateOrCountry>
            <com:zipCode>94583</com:zipCode>
          </address>
        </sellerDetails>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <saleDate>04/17/2023</saleDate>
        <amountOfSecuritiesSold>10000</amountOfSecuritiesSold>
        <grossProceeds>712320</grossProceeds>
      </securitiesSoldInPast3Months>
      <securitiesSoldInPast3Months>
        <sellerDetails>
          <name>Barry Zwarenstein and Mahbobeh Hirmand Trust</name>
          <address>
            <com:street1>C/o Five9, Inc.</com:street1>
            <com:street2>3001 Bishop Drive, Suite 350</com:street2>
            <com:city>San Ramon</com:city>
            <com:stateOrCountry>CA</com:stateOrCountry>
            <com:zipCode>94583</com:zipCode>
          </address>
        </sellerDetails>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <saleDate>05/17/2023</saleDate>
        <amountOfSecuritiesSold>2500</amountOfSecuritiesSold>
        <grossProceeds>137559</grossProceeds>
      </securitiesSoldInPast3Months>
      <securitiesSoldInPast3Months>
        <sellerDetails>
          <name>Barry Zwarenstein and Mahbobeh Hirmand Trust</name>
          <address>
            <com:street1>C/o Five9, Inc.</com:street1>
            <com:street2>3001 Bishop Drive, Suite 350</com:street2>
            <com:city>San Ramon</com:city>
            <com:stateOrCountry>CA</com:stateOrCountry>
            <com:zipCode>94583</com:zipCode>
          </address>
        </sellerDetails>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <saleDate>05/18/2023</saleDate>
        <amountOfSecuritiesSold>2500</amountOfSecuritiesSold>
        <grossProceeds>150055</grossProceeds>
      </securitiesSoldInPast3Months>
      <securitiesSoldInPast3Months>
        <sellerDetails>
          <name>Barry Zwarenstein and Mahbobeh Hirmand Trust</name>
          <address>
            <com:street1>C/o Five9, Inc.</com:street1>
            <com:street2>3001 Bishop Drive, Suite 350</com:street2>
            <com:city>San Ramon</com:city>
            <com:stateOrCountry>CA</com:stateOrCountry>
            <com:zipCode>94583</com:zipCode>
          </address>
        </sellerDetails>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <saleDate>05/22/2023</saleDate>
        <amountOfSecuritiesSold>2500</amountOfSecuritiesSold>
        <grossProceeds>162723</grossProceeds>
      </securitiesSoldInPast3Months>
      <securitiesSoldInPast3Months>
        <sellerDetails>
          <name>Barry Zwarenstein and Mahbobeh Hirmand Trust</name>
          <address>
            <com:street1>C/o Five9, Inc.</com:street1>
            <com:street2>3001 Bishop Drive, Suite 350</com:street2>
            <com:city>San Ramon</com:city>
            <com:stateOrCountry>CA</com:stateOrCountry>
            <com:zipCode>94583</com:zipCode>
          </address>
        </sellerDetails>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <saleDate>06/02/2023</saleDate>
        <amountOfSecuritiesSold>2500</amountOfSecuritiesSold>
        <grossProceeds>175114</grossProceeds>
      </securitiesSoldInPast3Months>
      <securitiesSoldInPast3Months>
        <sellerDetails>
          <name>Barry Zwarenstein and Mahbobeh Hirmand Trust</name>
          <address>
            <com:street1>C/o Five9, Inc.</com:street1>
            <com:street2>3001 Bishop Drive, Suite 350</com:street2>
            <com:city>San Ramon</com:city>
            <com:stateOrCountry>CA</com:stateOrCountry>
            <com:zipCode>94583</com:zipCode>
          </address>
        </sellerDetails>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <saleDate>06/09/2023</saleDate>
        <amountOfSecuritiesSold>7500</amountOfSecuritiesSold>
        <grossProceeds>562825</grossProceeds>
      </securitiesSoldInPast3Months>
      <securitiesSoldInPast3Months>
        <sellerDetails>
          <name>Barry Zwarenstein IRA</name>
          <address>
            <com:street1>C/o Five9, Inc.</com:street1>
            <com:street2>3001 Bishop Drive, Suite 350</com:street2>
            <com:city>San Ramon</com:city>
            <com:stateOrCountry>CA</com:stateOrCountry>
            <com:zipCode>94583</com:zipCode>
          </address>
        </sellerDetails>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <saleDate>06/05/2023</saleDate>
        <amountOfSecuritiesSold>10000</amountOfSecuritiesSold>
        <grossProceeds>696964</grossProceeds>
      </securitiesSoldInPast3Months>
      <securitiesSoldInPast3Months>
        <sellerDetails>
          <name>Barry Zwarenstein IRA</name>
          <address>
            <com:street1>C/o Five9, Inc.</com:street1>
            <com:street2>3001 Bishop Drive, Suite 350</com:street2>
            <com:city>San Ramon</com:city>
            <com:stateOrCountry>CA</com:stateOrCountry>
            <com:zipCode>94583</com:zipCode>
          </address>
        </sellerDetails>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <saleDate>06/09/2023</saleDate>
        <amountOfSecuritiesSold>2500</amountOfSecuritiesSold>
        <grossProceeds>187608</grossProceeds>
      </securitiesSoldInPast3Months>
      <noticeSignature>
        <noticeDate>07/13/2023</noticeDate>
        <planAdoptionDates>
          <planAdoptionDate>12/10/2022</planAdoptionDate>
        </planAdoptionDates>
        <signature>/s/ J.P. Morgan Securities LLC as agent and attorney-in-fact for Barry Zwarenstein</signature>
      </noticeSignature>
    </formData>
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metadata_documents: [{"type": "144", "sequence": "1", "filename": "primary_doc.xml", "secsgml_size_bytes": 8307}]
text: 144
  0001227348
  XXXXXXXX
  LIVE
  0001288847
  Five9, Inc.
  001-36383
  3001 Bishop Drive, Suite 350
  San Ramon
  CA
  94583
  925-201-2000
  Barry Zwarenstein
  Officer
  Common
  JP Morgan Securities LLC
  390 Madison Avenue
  6th Floor
  New York
  NY
  10017
  25000
  2159500
  71176473
  07/13/2023
  NASDAQ
  Common
  07/13/2023
  Stock Option Exercise
  Issuer
  N
  25000
  07/13/2023
  Cash
  N
  Barry Zwarenstein and Mahbobeh Hirmand Trust
  C/o Five9, Inc.
  3001 Bishop Drive, Suite 350
  San Ramon
  CA
  94583
  Common
  04/17/2023
  10000
  712320
  Barry Zwarenstein and Mahbobeh Hirmand Trust
  C/o Five9, Inc.
  3001 Bishop Drive, Suite 350
  San Ramon
  CA
  94583
  Common
  05/17/2023
  2500
  137559
  Barry Zwarenstein and Mahbobeh Hirmand Trust
  C/o Five9, Inc.
  3001 Bishop Drive, Suite 350
  San Ramon
  CA
  94583
  Common
  05/18/2023
  2500
  150055
  Barry Zwarenstein and Mahbobeh Hirmand Trust
  C/o Five9, Inc.
  3001 Bishop Drive, Suite 350
  San Ramon
  CA
  94583
  Common
  05/22/2023
  2500
  162723
  Barry Zwarenstein and Mahbobeh Hirmand Trust
  C/o Five9, Inc.
  3001 Bishop Drive, Suite 350
  San Ramon
  CA
  94583
  Common
  06/02/2023
  2500
  175114
  Barry Zwarenstein and Mahbobeh Hirmand Trust
  C/o Five9, Inc.
  3001 Bishop Drive, Suite 350
  San Ramon
  CA
  94583
  Common
  06/09/2023
  7500
  562825
  Barry Zwarenstein IRA
  C/o Five9, Inc.
  3001 Bishop Drive, Suite 350
  San Ramon
  CA
  94583
  Common
  06/05/2023
  10000
  696964
  Barry Zwarenstein IRA
  C/o Five9, Inc.
  3001 Bishop Drive, Suite 350
  San Ramon
  CA
  94583
  Common
  06/09/2023
  2500
  187608
  07/13/2023
  12/10/2022
  /s/ J.P. Morgan Securities LLC as agent and attorney-in-fact for Barry Zwarenstein