UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-Q/A

Amendment No. 1

For the quarterly period ended September 28, 2013

or

For the transition period              to              

Commission file number: 001-34133

GT Advanced Technologies Inc.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (603) 883-5200

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 o

Indicated 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 Regulations S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files). Yes x  No o

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 the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

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

As of June 13, 2014, approximately 137,174,027 shares of the registrant’s common stock, $0.01 par value per share, were issued and outstanding.

EXPLANATORY NOTE

This Amendment No. 1 to Form 10-Q (this “Amendment No. 1”) is being filed to amend our Quarterly Report on Form 10-Q for the fiscal quarter ended September 28, 2013 (the “Original Filing”), filed with the U.S. Securities and Exchange Commission (the “Commission”) on November 7, 2014 (the “Original Filing Date”). The sole purpose of this Amendment No. 1 is to file revised Exhibits 10.1, 10.2, 10.3 and 10.4 so that certain previously redacted provisions are disclosed in connection with the submission to the Commission of a confidential treatment request pursuant to Rule 24b-2 promulgated by the Commission under the Securities Exchange Act of 1934, as amended (the “Exchange Act”). The revised versions of Exhibits 10.1, 10.2, 10.3 and 10.4 supersede in their entirety Exhibits 10.1, 10.2, 10.3 and 10.4 to the Original Filing.

Pursuant to Rule 12b-15 under the Exchange Act, this Amendment No. 1 also contains new certifications pursuant to Section 302 of the Sarbanes-Oxley Act of 2002, which are attached hereto. Because no financial statements have been included in this Amendment No. 1 and this Amendment No. 1 does not contain or amend any disclosure with respect to Items 307 and 308 of Regulation S-K, paragraphs 3, 4, and 5 of the certifications have been omitted.

Except as described above, no changes have been made to the Original Filing, and this Amendment No. 1 does not modify, amend or update in any way any of the financial or other information contained in the Original Filing. This Amendment No. 1 does not reflect events that may have occurred subsequent to the Original Filing Date.

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Item 6.  Exhibits

Exhibits are incorporated by reference or are filed with this report as indicated below (numbered in accordance with Item 601 of Regulation S-K).

*                               Portions of this exhibit have been omitted and filed separately with the commission pursuant to a request for confidential treatment.

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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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