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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-01-25</periodOfReport>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001193456</rptOwnerCik>
            <rptOwnerName>ADAMS JAMES R</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>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-01-25</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>315411</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1450</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Partnership</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>271550</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3018.23</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust--401(k)</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>463.57</value>
                    <footnoteId id="F5"/>
                </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>29.79</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-01-25</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>7000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F6"/>
            </exerciseDate>
            <expirationDate>
                <value>2018-01-25</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>7000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F3">Shares held in trust for the benefit of family members of which reporting person is trustee.  Beneficial ownership by reporting person disclaimed.</footnote>
        <footnote id="F2">Shares held by family limited partnership of which the reporting person is a general partner.  Reporting person disclaims beneficial ownership except to the extent of his pecuniary interest in the partnership.</footnote>
        <footnote id="F6">The option becomes exercisable in four equal annual installments beginning on January 25, 2009.</footnote>
        <footnote id="F5">Estimated shares attributable to TI Universal Profit Sharing Account as of 12-31-07.  (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 12-31-07 that are eligible for deferred reporting on Form 5.</footnote>
        <footnote id="F1">Award of restricted stock units granted under the Texas Instruments 2003 Director Compensation Plan.</footnote>
        <footnote id="F4">Estimated shares attributable to TI 401(k) Account as of 12-31-07.   (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 this account occurring after 12-31-07 that are eligible for deferred reporting on Form 5.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>DANIEL M. DRORY, ATTORNEY IN FACT</signatureName>
        <signatureDate>2008-01-29</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0202
4
2008-01-25
0000097476
TEXAS INSTRUMENTS INC
TXN
0001193456
ADAMS JAMES R
12500 TI BOULEVARD
DALLAS
TX
75243
1
0
0
0
Common Stock
2008-01-25
4
A
0
2500
0
A
315411
D
Common Stock
1450
I
By Partnership
Common Stock
271550
I
By Trust
Common Stock
3018.23
I
By Trust--401(k)
Common Stock
463.57
I
By Trust--PS
NQ Stock Option (right to buy)
29.79
2008-01-25
4
A
0
7000
0
A
2018-01-25
Common Stock
7000
7000
D
Shares held in trust for the benefit of family members of which reporting person is trustee.  Beneficial ownership by reporting person disclaimed.
Shares held by family limited partnership of which the reporting person is a general partner.  Reporting person disclaims beneficial ownership except to the extent of his pecuniary interest in the partnership.
The option becomes exercisable in four equal annual installments beginning on January 25, 2009.
Estimated shares attributable to TI Universal Profit Sharing Account as of 12-31-07.  (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 12-31-07 that are eligible for deferred reporting on Form 5.
Award of restricted stock units granted under the Texas Instruments 2003 Director Compensation Plan.
Estimated shares attributable to TI 401(k) Account as of 12-31-07.   (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 this account occurring after 12-31-07 that are eligible for deferred reporting on Form 5.
DANIEL M. DRORY, ATTORNEY IN FACT
2008-01-29