<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2006-01-19</periodOfReport>

    <issuer>
        <issuerCik>0000097476</issuerCik>
        <issuerName>TEXAS INSTRUMENTS INC</issuerName>
        <issuerTradingSymbol>TXN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001194832</rptOwnerCik>
            <rptOwnerName>ENGIBOUS THOMAS J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>12500 TI BOULEVARD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75243</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chairman of the Board</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>123187.52</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>261.16</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust--CODA</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>17733.52</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust--PS</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>NQ Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>32.55</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2006-01-19</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>270000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2019-01-19</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>270000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>270000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F3">The option becomes exercisable in four equal annual installments beginning on January 19, 2007.</footnote>
        <footnote id="F1">Estimated shares attributable to TI Employee Cash or Deferred Compensation Account as of 12-31-05.  (Interests in this account are denominated in units.  Consequently, share amount shown is an estimate.)  This statement does not include changes in beneficial ownership of shares held in such account occurring after 12-31-05 that are eligible for deferred reporting on Form 5.</footnote>
        <footnote id="F2">Estimated shares attributable to TI Universal Profit Sharing account as of 12-31-05.  (Interests in this account are denominated in units.  Consequently, share amount shown is an estimate.)  This statement does not include changes in beneficial ownership of shares held in such account occurring after 12-31-05 that are eligible for deferred reporting on Form 5.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>DANIEL M. DRORY, ATTORNEY IN FACT</signatureName>
        <signatureDate>2006-01-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0202
4
2006-01-19
0000097476
TEXAS INSTRUMENTS INC
TXN
0001194832
ENGIBOUS THOMAS J
12500 TI BOULEVARD
DALLAS
TX
75243
1
1
0
0
Chairman of the Board
Common Stock
123187.52
D
Common Stock
261.16
I
By Trust--CODA
Common Stock
17733.52
I
By Trust--PS
NQ Stock Option (right to buy)
32.55
2006-01-19
4
A
0
270000
0
A
2019-01-19
Common Stock
270000
270000
D
The option becomes exercisable in four equal annual installments beginning on January 19, 2007.
Estimated shares attributable to TI Employee Cash or Deferred Compensation Account as of 12-31-05.  (Interests in this account are denominated in units.  Consequently, share amount shown is an estimate.)  This statement does not include changes in beneficial ownership of shares held in such account occurring after 12-31-05 that are eligible for deferred reporting on Form 5.
Estimated shares attributable to TI Universal Profit Sharing account as of 12-31-05.  (Interests in this account are denominated in units.  Consequently, share amount shown is an estimate.)  This statement does not include changes in beneficial ownership of shares held in such account occurring after 12-31-05 that are eligible for deferred reporting on Form 5.
DANIEL M. DRORY, ATTORNEY IN FACT
2006-01-19