UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q/A

Amendment No. 1

for the Quarterly Period Ended December 31, 2013

OR

for the transition period from                      to                     

Commission file number 001-13601

GEOSPACE TECHNOLOGIES CORPORATION

(Exact Name of Registrant as Specified in Its Charter)

(713) 986-4444

(Registrant’s telephone number, including area code)

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 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 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  ¨    No  x

There were 13,134,416 shares of the Registrant’s Common Stock outstanding as of the close of business on January 31, 2014.

EXPLANATORY NOTE

This Amendment No. 1 to the Quarterly Report on Form 10-Q/A of Geospace Technologies Corporation and its subsidiaries (the “Company”) for the three months ended December 31, 2013 is being filed to amend and restate Part I. Item 4. Controls and Procedures.

The Company’s previous Form 10-Q filed on February 6, 2014 (the “Original Report”) did not include management’s conclusion regarding the effectiveness of disclosure controls and procedures as of December 31, 2013 as required by Item 307 of Regulation S-K and Exchange Act Rule 13a-15(b). In addition, the Company included a statement in the Original Report that it had assessed its internal controls over financial reporting as of the quarter ended December 31, 2013 which should not have been presented.

This amended Quarterly Report on Form 10-Q/A should be read in conjunction with the Original Report and the Company’s annual report on Form 10-K for the fiscal year ended September 30, 2013 and subsequent filings with the Securities and Exchange Commission (the “SEC”). In addition, in accordance with applicable SEC rules, this amended Quarterly Report on Form 10-Q/A includes updated certificates from our chief executive officer and chief financial officer as Exhibits 31.1, 31.2, 32.1 and 32.2.

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Item 4. Controls and Procedures

Our management is responsible for establishing and maintaining a system of disclosure controls and procedures that are designed to ensure that information required to be disclosed in our reports filed under the Exchange Act is recorded, processed, summarized and reported within the time periods specified under the Securities and Exchange Commission’s rules and forms, and that such information is accumulated and communicated to our management, including our Chief Executive Officer (“CEO”) and Chief Financial Officer (“CFO”). Notwithstanding the foregoing, there can be no assurance that the Company’s disclosure controls and procedures will detect or uncover all failures of persons within the Company and its consolidated subsidiaries to report material information otherwise required to be set forth in the Company’s reports.

In connection with the preparation of this Quarterly Report on Form 10-Q, the Company carried out an evaluation under the supervision and with the participation of the Company’s management, including the CEO and CFO, as of December 31, 2013 of the effectiveness of the Company’s disclosure controls and procedures, as such term is defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act. Based on that evaluation, the CEO and CFO concluded that our disclosure controls and procedures were effective as of December 31, 2013.

There were no changes in the Company’s internal control over financial reporting that occurred during the Company’s fiscal quarter ended December 31, 2013 that have materially affected, or are reasonably likely to materially affect, the Company’s internal control over financial reporting.

PART II—OTHER INFORMATION

Item 6. Exhibits

The following exhibits are filed with this Report on Form 10-Q.

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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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