UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d) OF THE

SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): March 27, 2013

MARINEMAX, INC.

(Exact Name of Registrant as Specified in its Charter)

Registrant’s telephone number, including area code: (727) 531-1700

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2 below):

Dismissal of Previous Independent Registered Public Accounting Firm

On March 27, 2013, MarineMax, Inc. (the “Company”) dismissed its independent registered public accounting firm, Ernst & Young LLP (“Ernst & Young”), effective as of that date. The decision to change independent registered public accounting firms was approved by the Company’s Audit Committee, upon completion of a competitive review process.

Ernst & Young’s reports on the Company’s consolidated financial statements and the effectiveness of internal control over financial reporting as of and for the fiscal years ended September 30, 2012 and 2011 did not contain an adverse opinion or disclaimer of opinion and were not qualified or modified as to uncertainty, audit scope or accounting principles.

During the fiscal years ended September 30, 2012 and 2011, and the subsequent interim period through March 27, 2013, there were (i) no “disagreements” as that term is defined in Item 304(a)(1)(iv) of Regulation S-K, between the Company and Ernst & Young on any matter of accounting principles or practices, financial statement disclosure or auditing scope or procedure, which disagreements, if not resolved to the satisfaction of Ernst & Young, would have caused Ernst & Young to make reference to the subject matter of the disagreement in its reports on the financial statements for such years, and (ii) no “reportable events” as that term is defined in Item 304(a)(1)(v) of Regulation S-K.

The Company has provided Ernst & Young with a copy of the foregoing disclosures and requested that Ernst & Young furnish the Company with a letter addressed to the Securities and Exchange Commission (“SEC”) stating whether or not it agrees with the statements in the above paragraphs. Ernst & Young’s letter to the SEC stating whether it agrees with such statements is filed as Exhibit 16.1 to this Current Report on Form 8-K.

Appointment of New Independent Registered Public Accounting Firm

On March 27, 2013, the Company engaged KPMG LLP (“KPMG”) as its new independent registered public accounting firm, effective immediately. The decision to engage KPMG as the Company’s independent registered public accounting firm was approved by the Company’s Audit Committee. During the fiscal years ended September 30, 2012 and 2011, and through March 27, 2013, the date of KPMG’s engagement, neither the Company, nor anyone acting on its behalf, consulted KPMG regarding either (i) the application of accounting principles to a specified transaction, either completed or proposed, or the type of audit opinion that might be rendered with respect to the consolidated financial statements of the Company, in any case where a written report or oral advice was provided to the Company by KPMG that KPMG concluded was an important factor considered by the Company in reaching a decision as to any accounting, auditing or financial reporting issue; or (ii) any matter that was the subject of a disagreement (as that term is defined in Item 304(a)(1)(iv) of Regulation S-K and the related instructions) or a “reportable event” (as that term is defined in Item 304(a)(1)(v) of Regulation S-K).

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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 hereunto duly authorized.

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