UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 10-Q/A

(Amendment No. 1)

(Mark One)

For the quarterly period ended July 31, 2012

OR

For the transition period from to

Commission File Number 0-23248

SIGMATRON INTERNATIONAL, INC.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (847) 956-8000

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files.    Yes  x    No  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See definition of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act.

Indicate by check mark whether the registrant is a shell company (as defined by Rule 12b-2 of the Exchange Act).    Yes  ¨    No  x

Indicate the number of shares outstanding of the registrant’s common stock, $0.01 par value, as of September 14, 2012: 3,930,402

Explanatory Note

This Amendment No. 1 (the “Amendment”) to the Registrant’s Quarterly Report on Form 10-Q for the period ended July 31, 2012, originally filed with the Securities Exchange Commission on September 14, 2012 (the “Original Filing”), is being filed solely to furnish the Interactive Data File exhibits required pursuant to Rule 405 of Regulation S-T.

No other changes have been made to the Original Filing, other than the furnishing of the exhibits mentioned above. The Amendment does not reflect subsequent events occurring after the date of the Original Filing or modify or update any disclosures set forth in the Original Filing.

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The following exhibits are included as part of this report and are filed herewith:

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SIGNATURES:

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

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