<?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>48000</noOfUnitsSold>
            <aggregateMarketValue>4605120.00</aggregateMarketValue>
            <noOfUnitsOutstanding>50670271</noOfUnitsOutstanding>
            <approxSaleDate>05/23/2024</approxSaleDate>
            <securitiesExchangeName>NASDAQ</securitiesExchangeName>
        </securitiesInformation>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>05/23/2024</acquiredDate>
            <natureOfAcquisitionTransaction>Exercise of Stock Options</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>48000</amountOfSecuritiesAcquired>
            <paymentDate>05/23/2024</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.&#13;
The date of acquisition and payment was and will be the date of exercise/sale.&#13;
</remarks>
        <noticeSignature>
            <noticeDate>05/23/2024</noticeDate>
            <planAdoptionDates>
                <planAdoptionDate>02/22/2024</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
48000
4605120.00
50670271
05/23/2024
NASDAQ
Common
05/23/2024
Exercise of Stock Options
Issuer
N
48000
05/23/2024
Cash
Y
The securities to be sold were and will be received upon the exercise of stock options over the next three months.
The date of acquisition and payment was and will be the date of exercise/sale.
05/23/2024
02/22/2024
/s/ Paul R Johnston