<?xml version="1.0" encoding="us-ascii"?><InstanceReport xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><Version>2.4.0.8</Version><ReportLongName>0012 - Disclosure - Going Concern</ReportLongName><DisplayLabelColumn>true</DisplayLabelColumn><ShowElementNames>false</ShowElementNames><RoundingOption /><HasEmbeddedReports>false</HasEmbeddedReports><Columns><Column FlagID="0"><Id>1</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

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</LabelSeparator><Level>1</Level><ElementName>us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract</ElementName><ElementPrefix>us-gaap_</ElementPrefix><IsBaseElement>true</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText /><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>xbrli:stringItemType</ElementDataType><SimpleDataType>string</SimpleDataType><IsTotalLabel>false</IsTotalLabel><UnitID>0</UnitID><Label>Organization, Consolidation and Presentation of Financial Statements [Abstract]</Label></Row><Row FlagID="0"><Id>2</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><Level>2</Level><ElementName>us-gaap_LiquidityDisclosureTextBlock</ElementName><ElementPrefix>us-gaap_</ElementPrefix><IsBaseElement>true</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="From2012-10-01to2013-06-30" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText>&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 27pt"&gt;&amp;#160;&amp;#160;&amp;#160;
The consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets
and settlement of obligations in the normal course of business. The Company generated significant net losses in the current and
previous fiscal years.&amp;#160;&amp;#160;The Company had approximately $146,000 of cash on hand as of June 30, 2013.&amp;#160;&amp;#160;The Company&amp;#146;s
operating expenses during the quarter ended June 30, 2013 was approximately $4,085,000.&amp;#160;&amp;#160;The Company expects that it
will need to raise significant additional capital to continue as a going concern.&lt;/p&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-indent: 0.5in"&gt;&amp;#160;&lt;/p&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 9pt"&gt;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;
For the three and nine months ended June 30, 2013, the Company&amp;#146;s loss from continuing operations was $3.7 million and $12.7
million respectively, as compared to the Company&amp;#146;s income from continuing operations for the three months ended July 1, 2012
of $8.3 million and the Company&amp;#146;s loss from continuing operations for the nine months ended July 1, 2012 of $16.5 million.
&amp;#160;As of June 30, 2013 the Company had negative working capital and stockholders&amp;#146; deficit of approximately $26.3 million
and $45.7 million respectively, and as of September 30, 2012, the Company had negative working capital and stockholders&amp;#146;
deficit of $10.1 million and $35.4 million, respectively.&lt;/p&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 0.5in"&gt;&amp;#160;&lt;/p&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 27pt"&gt;&amp;#160;&amp;#160;&amp;#160;
Management believes that the Company&amp;#146;s losses in recent years have been primarily the result of increased research and development
expenditures related to the cyber technology, and efforts to productize those technologies and bring them to market.&amp;#160;&amp;#160;These
losses were augmented by insufficient revenue to support the Company&amp;#146;s skilled and diverse technical staff, which is considered
necessary to support commercialization of the Company&amp;#146;s technologies.&amp;#160;&amp;#160;Unsuccessful commercialization efforts in
past fiscal years have contributed to the stockholders&amp;#146; deficit as of June 30, 2013. Through June 30, 2013, the Company expended
substantially all of the cash obtained from the Thermal Imaging Sale,&amp;#160;the Revolving Credit Facility (defined below), and 2013
Notes (see Note 7) to fund our operations.&lt;/p&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-indent: 0.5in"&gt;&amp;#160;&lt;/p&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 27pt"&gt;&amp;#160;&amp;#160;&amp;#160;
Management is currently focused on seeking additional capital to fund operations and on managing costs in line with estimated future
revenues, including contingencies for cost reductions if projected revenues are not fully realized.&amp;#160; However, there can be
no assurance that the Company will be able to obtain additional working capital, or that anticipated revenues will be realized.&amp;#160;&amp;#160;In
the event the Company is unable to raise additional funds to meet its continuing obligations on a timely basis, or at all, or the
Company is unable to meet existing debt obligations, a default and acceleration of debt maturity could result, which could materially
and adversely affect the Company&amp;#146;s business and financial condition, and ultimately challenge the Company&amp;#146;s ability
to continue as a going concern.&lt;/p&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-indent: 0.5in"&gt;&amp;#160;&lt;/p&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 27pt"&gt;&amp;#160;&amp;#160;&amp;#160;&amp;#160;The
accompanying consolidated financial statements do not include any adjustments relating to the recoverability and classification
of asset carrying amounts or the amount and classification of liabilities that might result should the Company be unable to continue
as a going concern.&amp;#160;&lt;/p&gt;</NonNumbericText><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>nonnum:textBlockItemType</ElementDataType><SimpleDataType>na</SimpleDataType><ElementDefenition>Disclosure of accounting policy for reporting when there is a substantial doubt about an entity's ability to continue as a going concern for a reasonable period of time (generally a year from the balance sheet date). Disclose: (a) pertinent conditions and events giving rise to the assessment of substantial doubt about the entity's ability to continue as a going concern for a reasonable period of time, (b) the possible effects of such conditions and events, (c) management's evaluation of the significance of those conditions and events and any mitigating factors, (d) possible discontinuance of operations, (e) management's plans (including relevant prospective financial information), and (f) information about the recoverability or classification of recorded asset amounts or the amounts or classification of liabilities. If management's plans alleviate the substantial doubt about the entity's ability to continue as a going concern, disclosure of the principal conditions and events that initially raised the substantial doubt about the entity's ability to continue as a going concern would be expected to be considered. Disclose whether operations for the current or prior years generated sufficient cash to cover current obligations, whether waivers were obtained from creditors relating to the company's default under the provisions of debt agreements and possible effects of such conditions and events, such as: whether there is a possible need to obtain additional financing (debt or equity) or to liquidate certain holdings to offset future cash flow deficiencies. Disclose appropriate parent company information when parent is dependent upon remittances from subsidiaries to satisfy its obligations.</ElementDefenition><ElementReferences>No definition available.</ElementReferences><IsTotalLabel>false</IsTotalLabel><UnitID>0</UnitID><Label>Going Concern</Label></Row></Rows><Footnotes /><IsEquityReport>false</IsEquityReport><ReportName>Going Concern</ReportName><MonetaryRoundingLevel>UnKnown</MonetaryRoundingLevel><SharesRoundingLevel>UnKnown</SharesRoundingLevel><PerShareRoundingLevel>UnKnown</PerShareRoundingLevel><ExchangeRateRoundingLevel>UnKnown</ExchangeRateRoundingLevel><HasCustomUnits>true</HasCustomUnits><IsEmbedReport>false</IsEmbedReport><IsMultiCurrency>false</IsMultiCurrency><ReportType>Sheet</ReportType><RoleURI>http://irvine-sensors.com/role/GoingConcern</RoleURI><NumberOfCols>1</NumberOfCols><NumberOfRows>2</NumberOfRows></InstanceReport>
