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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-08-31</periodOfReport>

    <issuer>
        <issuerCik>0001288776</issuerCik>
        <issuerName>Google Inc.</issuerName>
        <issuerTradingSymbol>GOOG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001468233</rptOwnerCik>
            <rptOwnerName>Arora Nikesh</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O GOOGLE INC.</rptOwnerStreet1>
            <rptOwnerStreet2>1600 AMPHITHEATRE PARKWAY</rptOwnerStreet2>
            <rptOwnerCity>MOUNTAIN VIEW</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94043</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isOfficer>1</isOfficer>
            <officerTitle>Pres, Global Sales &amp; Bus Dev</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Class A Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2012</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Google Stock Unit</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Google Stock Unit</value>
                <footnoteId id="F2"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>17069</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Google Stock Unit</value>
                <footnoteId id="F3"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>30928</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Google Stock Unit</value>
                <footnoteId id="F4"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>27107</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Option To Purchase Class A Common Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>306.00</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-08-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>156</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>180.25</value>
                    <footnoteId id="F6"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <value>2015-09-28</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>156</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>157</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeHolding>
            <securityTitle>
                <value>Option To Purchase Class A Common Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>308.57</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F7"/>
            </exerciseDate>
            <expirationDate>
                <value>2016-05-17</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>8050</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8050</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Option To Purchase Class A Common Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>308.57</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F8"/>
            </exerciseDate>
            <expirationDate>
                <value>2016-11-22</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>12000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>12000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Option To Purchase Class A Common Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>308.57</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F9"/>
            </exerciseDate>
            <expirationDate>
                <value>2017-10-05</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>10000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Option To Purchase Class A Common Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>308.57</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F10"/>
            </exerciseDate>
            <expirationDate>
                <value>2017-10-05</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>7000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Option To Purchase Class A Common Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>318.92</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F11"/>
            </exerciseDate>
            <expirationDate>
                <value>2019-03-04</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>34138</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>34138</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The Google Stock Units (&quot;GSUs&quot;) entitle the reporting person to receive one share of Google Inc.'s Class A Common Stock for each share underlying the GSU as the GSU vests. The GSUs vest as follows: 500 of the GSUs shall vest on 9/7/09 and 500 of the GSUs shall vest on 12/7/09.</footnote>
        <footnote id="F2">The Google Stock Units (&quot;GSUs&quot;) entitle the reporting person to receive one share of Google Inc.'s Class A Common Stock for each share underlying the GSU as the GSU vests. The GSUs vest as follows: 4,267 of the GSUs shall vest on 3/4/10 and 1/16th of the GSUs shall vest each quarter thereafter until the units are fully vested, subject to continued employment with Google on the applicable vesting dates.</footnote>
        <footnote id="F3">The Google Stock Units (&quot;GSUs&quot;) entitle the reporting person to receive one share of Google Inc.'s Class A Common Stock for each share underlying the GSU as the GSU vests. The GSUs vest as follows: 2,812 of the GSUs shall vest on 9/5/09, 2,811 of the GSUs shall vest on 12/5/09, 2,812 of the GSUs shall vest on 3/5/10, 2,812 of the GSUs shall vest on 6/5/10, 2,811 of the GSUs shall vest on 9/5/10, 2,812 of the GSUs shall vest on 12/5/10, 2,811 of the GSUs shall vest on 3/5/11, 2,812 of the GSUs shall vest on 6/5/11, 2,811 of the GSUs shall vest on 9/5/11, 2,812 of the GSUs shall vest on 12/5/11 and 2,812 of the GSUs shall vest on 3/5/12, subject to continued employment with Google on the applicable vesting dates.</footnote>
        <footnote id="F4">The Google Stock Units (&quot;GSUs&quot;) entitle the reporting person to receive one share of Google Inc.'s Class A Common Stock for each share underlying the GSU as the GSU vests. The GSUs vest as follows: 6,776 of the GSUs shall vest on 4/15/10 and 1/16th of the GSUs shall vest each quarter thereafter until the units are fully vested, subject to continued employment with Google on the applicable vesting dates.</footnote>
        <footnote id="F5">469 shares subject to the option are fully vested and exercisable.  The option provides for vesting of the remaining option shares as follows: 156 shares shall vest on 7/28/09, 156 shares shall vest on 8/28/09, and 157 shares shall vest on 9/28/09, subject to continued employment with Google on the applicable vesting dates.</footnote>
        <footnote id="F6">The sale was made through Google's Transferable Stock Option (&quot;TSO&quot;) program, pursuant to which vested stock options are sold to institutional investors in an online auction.</footnote>
        <footnote id="F7">The option provides for vesting as follows: 1,749 shares shall vest on 9/9/09, 234 shares shall vest on 9/17/09, 233 shares shall vest on 10/17/09, 233 shares shall vest on 11/17/09, 234 shares shall vest on 12/17/09, 233 shares shall vest on 1/17/10, 233 shares shall vest on 2/17/10, 234 shares shall vest on 3/17/10, 233 shares shall vest on 4/17/10, 234 shares shall vest on 5/17/10 and 350 shares shall vest each month thereafter until the option is fully vested, subject to continued employment with Google on the applicable vesting dates.</footnote>
        <footnote id="F8">The option provides for vesting as follows: 5,250 shares shall vest on 9/9/09 and 1/48th of the total option shall vest on 9/22/09 and each month thereafter until the option is fully vested, subject to continued employment with Google on the applicable vesting dates.</footnote>
        <footnote id="F9">The option provides for vesting as follows: 2,500 shares shall vest on 10/5/09 and 1/48th of the total option shall vest each month thereafter until the option is fully vested, subject to continued employment with Google on the applicable vesting dates.</footnote>
        <footnote id="F10">The option provides for vesting as follows: 1,750 shares shall vest on 10/5/09 and 1/48th of the total option shall vest each month thereafter until the option is fully vested, subject to continued employment with Google on the applicable vesting dates.</footnote>
        <footnote id="F11">The option provides for vesting as follows: 8,534 shares shall vest on 3/4/10 and 1/48th of the total option shall vest each month thereafter until the option is fully vested, subject to continued employment with Google on the applicable vesting dates.</footnote>
    </footnotes>

    <remarks>***All of the sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person.***</remarks>

    <ownerSignature>
        <signatureName>/s/ Jonathan Frankel, attorney-in-fact for Nikesh Arora</signatureName>
        <signatureDate>2009-09-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
