<?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/ownership" xmlns:ns2="http://www.sec.gov/edgar/common">
    <headerData>
        <submissionType>144</submissionType>
        <filerInfo>
            <filer>
                <filerCredentials>
                    <cik>0001580111</cik>
                    <ccc>XXXXXXXX</ccc>
                </filerCredentials>
            </filer>
            <liveTestFlag>LIVE</liveTestFlag>



        </filerInfo>
    </headerData>
    <formData>
        <issuerInfo>
            <issuerCik>0001923840</issuerCik>
            <issuerName>THIRD HARMONIC BIO INC</issuerName>
            <secFileNumber>001-41498</secFileNumber>
            <issuerAddress>
                <ns2:street1>1700 Montgomery Street Suite 210</ns2:street1>
                <ns2:city>San Francisco</ns2:city>
                <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                <ns2:zipCode>94111</ns2:zipCode>
            </issuerAddress>
            <issuerContactPhone>2097272457</issuerContactPhone>
            <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>NATALIE HOLLES</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
            <relationshipsToIssuer>
                <relationshipToIssuer>Director</relationshipToIssuer>
                <relationshipToIssuer>Officer</relationshipToIssuer>
            </relationshipsToIssuer>
        </issuerInfo>
        <securitiesInformation>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <brokerOrMarketmakerDetails>
                <name>Morgan Stanley Smith Barney LLC Executive Financial Services</name>
                <address>
                    <ns2:street1>1 New York Plaza</ns2:street1>
                    <ns2:street2>8th Floor</ns2:street2>
                    <ns2:city>New York</ns2:city>
                    <ns2:stateOrCountry>NY</ns2:stateOrCountry>
                    <ns2:zipCode>10004</ns2:zipCode>
                </address>
            </brokerOrMarketmakerDetails>
            <noOfUnitsSold>45040</noOfUnitsSold>
            <aggregateMarketValue>537777.60</aggregateMarketValue>
            <noOfUnitsOutstanding>40714399</noOfUnitsOutstanding>
            <approxSaleDate>04/11/2024</approxSaleDate>
            <securitiesExchangeName>NASDAQ</securitiesExchangeName>
        </securitiesInformation>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>04/11/2024</acquiredDate>
            <natureOfAcquisitionTransaction>Exercise of Stock Options</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>45040</amountOfSecuritiesAcquired>
            <paymentDate>04/11/2024</paymentDate>
            <natureOfPayment>Cash</natureOfPayment>
        </securitiesToBeSold>
        <nothingToReportFlagOnSecuritiesSoldInPast3Months>Y</nothingToReportFlagOnSecuritiesSoldInPast3Months>
        <remarks>The securities to be sold were and will be received upon the exercise of stock options over the next three months. The dates of acquisition and payment were and will be the dates of exercise/sale.
</remarks>
        <noticeSignature>
            <noticeDate>04/11/2024</noticeDate>
            <planAdoptionDates>
                <planAdoptionDate>09/25/2023</planAdoptionDate>
            </planAdoptionDates>
            <signature>/s/ Natalie Holles</signature>
        </noticeSignature>
    </formData>
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144
0001580111
XXXXXXXX
LIVE
0001923840
THIRD HARMONIC BIO INC
001-41498
1700 Montgomery Street Suite 210
San Francisco
CA
94111
2097272457
NATALIE HOLLES
Director
Officer
Common
Morgan Stanley Smith Barney LLC Executive Financial Services
1 New York Plaza
8th Floor
New York
NY
10004
45040
537777.60
40714399
04/11/2024
NASDAQ
Common
04/11/2024
Exercise of Stock Options
Issuer
N
45040
04/11/2024
Cash
Y
The securities to be sold were and will be received upon the exercise of stock options over the next three months. The dates of acquisition and payment were and will be the dates of exercise/sale.
04/11/2024
09/25/2023
/s/ Natalie Holles