<?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>0001193221</cik>
                    <ccc>XXXXXXXX</ccc>
                </filerCredentials>
            </filer>
            <liveTestFlag>LIVE</liveTestFlag>



        </filerInfo>
    </headerData>
    <formData>
        <issuerInfo>
            <issuerCik>0000851520</issuerCik>
            <issuerName>EXPONENT INC</issuerName>
            <secFileNumber>000-18655</secFileNumber>
            <issuerAddress>
                <ns2:street1>149 COMMONWEALTH DRIVE</ns2:street1>
                <ns2:city>MENLO PARK</ns2:city>
                <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                <ns2:zipCode>94025</ns2:zipCode>
            </issuerAddress>
            <issuerContactPhone>6503269400</issuerContactPhone>
            <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>PAUL R JOHNSTON</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
            <relationshipsToIssuer>
                <relationshipToIssuer>Director</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>42000</noOfUnitsSold>
            <aggregateMarketValue>4124820.00</aggregateMarketValue>
            <noOfUnitsOutstanding>50764457</noOfUnitsOutstanding>
            <approxSaleDate>11/06/2024</approxSaleDate>
            <securitiesExchangeName>NASDAQ</securitiesExchangeName>
        </securitiesInformation>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>11/06/2024</acquiredDate>
            <natureOfAcquisitionTransaction>Exercise of Stock Options</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>42000</amountOfSecuritiesAcquired>
            <paymentDate>11/06/2024</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.&#13;
</remarks>
        <noticeSignature>
            <noticeDate>11/06/2024</noticeDate>
            <planAdoptionDates>
                <planAdoptionDate>07/30/2024</planAdoptionDate>
            </planAdoptionDates>
            <signature>/s/ Paul R Johnston</signature>
        </noticeSignature>
    </formData>
</edgarSubmission>
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144
0001193221
XXXXXXXX
LIVE
0000851520
EXPONENT INC
000-18655
149 COMMONWEALTH DRIVE
MENLO PARK
CA
94025
6503269400
PAUL R JOHNSTON
Director
Common
Morgan Stanley Smith Barney LLC Executive Financial Services
1 New York Plaza
8th Floor
New York
NY
10004
42000
4124820.00
50764457
11/06/2024
NASDAQ
Common
11/06/2024
Exercise of Stock Options
Issuer
N
42000
11/06/2024
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.
11/06/2024
07/30/2024
/s/ Paul R Johnston