content: <?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/ownership" xmlns:com="http://www.sec.gov/edgar/common">
    <!-- Generated by Workiva -->
    <headerData>
      <submissionType>144</submissionType>
      <filerInfo>
        <filer>
          <filerCredentials>
            <cik>0001753224</cik>
            <ccc>XXXXXXXX</ccc>
          </filerCredentials>
        </filer>
        <liveTestFlag>LIVE</liveTestFlag>
  
  
  
      </filerInfo>
    </headerData>
    <formData>
      <issuerInfo>
        <issuerCik>0001722964</issuerCik>
        <issuerName>Y-mAbs Therapeutics, Inc.</issuerName>
        <secFileNumber>001-38650</secFileNumber>
        <issuerAddress>
          <com:street1>230 Park Avenue</com:street1>
          <com:street2>Suite3350</com:street2>
          <com:city>New York</com:city>
          <com:stateOrCountry>NY</com:stateOrCountry>
          <com:zipCode>10169</com:zipCode>
        </issuerAddress>
        <issuerContactPhone>6468858505</issuerContactPhone>
        <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>Thomas Gad</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
        <relationshipsToIssuer>
          <relationshipToIssuer>Officer</relationshipToIssuer>
        </relationshipsToIssuer>
      </issuerInfo>
      <securitiesInformation>
        <securitiesClassTitle>Common Stock</securitiesClassTitle>
        <brokerOrMarketmakerDetails>
          <name>J.P. 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>100000</noOfUnitsSold>
        <aggregateMarketValue>1193000</aggregateMarketValue>
        <noOfUnitsOutstanding>43882638</noOfUnitsOutstanding>
        <approxSaleDate>05/21/2024</approxSaleDate>
        <securitiesExchangeName>Nasdaq</securitiesExchangeName>
      </securitiesInformation>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>08/15/2015</acquiredDate>
        <natureOfAcquisitionTransaction>Private Investment</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>100000</amountOfSecuritiesAcquired>
        <paymentDate>08/15/2015</paymentDate>
        <natureOfPayment>Cash</natureOfPayment>
      </securitiesToBeSold>
      <nothingToReportFlagOnSecuritiesSoldInPast3Months>Y</nothingToReportFlagOnSecuritiesSoldInPast3Months>
      <remarks>The shares filed today will be sold by Gad Enterprises, LLC, Thomas Gad, Manager</remarks>
      <noticeSignature>
        <noticeDate>05/21/2024</noticeDate>
        <signature>/s/ J.P. Morgan Securities LLC as agent and attorney-in-fact for Thomas Gad</signature>
      </noticeSignature>
    </formData>
  </edgarSubmission>
metadata_documents: [{"type": "144", "sequence": "1", "filename": "primary_doc.xml", "secsgml_size_bytes": 2990}]
text: 144
  0001753224
  XXXXXXXX
  LIVE
  0001722964
  Y-mAbs Therapeutics, Inc.
  001-38650
  230 Park Avenue
  Suite3350
  New York
  NY
  10169
  6468858505
  Thomas Gad
  Officer
  Common Stock
  J.P. Morgan Securities LLC
  390 Madison Avenue
  6th Floor
  New York
  NY
  10017
  100000
  1193000
  43882638
  05/21/2024
  Nasdaq
  Common
  08/15/2015
  Private Investment
  Issuer
  N
  100000
  08/15/2015
  Cash
  Y
  The shares filed today will be sold by Gad Enterprises, LLC, Thomas Gad, Manager
  05/21/2024
  /s/ J.P. Morgan Securities LLC as agent and attorney-in-fact for Thomas Gad