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): August 20, 2012

Thor Industries, Inc.

(Exact Name of Registrant as Specified in Charter)

Registrant’s telephone number, including area code: (937) 596-6849

N/A

(Former Name or Former Address, if Changed Since Last Report)

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:

On August 21, 2012, Thor Industries, Inc. (the “Company”) issued a press release announcing that Richard E. Riegel, III will resign from his position as Senior Group President of the Company effective September 30, 2012 (the “Resignation Date”) to pursue other business interests.

In connection with Mr. Riegel’s resignation, the Company and Mr. Riegel entered into a one year consulting arrangement, the terms of which are memorialized in a letter from the Company dated August 17, 2012 and acknowledged by Mr. Riegel on August 20, 2012 (the “Letter of Understanding”). In accordance with the Letter of Understanding, the Company has agreed to provide Mr. Riegel with (i) compensation in the aggregate amount of $300,000, payable in biweekly or monthly installments over the one year consulting period, (ii) use of his current office in New York City during the one year consulting period, provided that the space is still available to the Company, (iii) reimbursement of unreimbursed reasonable and necessary out-of-pocket business, travel, and entertainment expenses incurred by Mr. Riegel prior to the Resignation Date in the performance of his duties and responsibilities during his employment with the Company (subject to the Company’s policies and procedures for expense verification and documentation), and (iv) the right to elect to continue health and dental insurance coverage under COBRA for a period of up to eighteen (18) months to the extent such coverage is available under the Company’s health plans and provided that Mr. Riegel is eligible and fulfills his coverage obligations. All of Mr. Riegel’s stock options that have vested as of the Resignation Date will be subject to the terms and conditions of the applicable stock option agreements. All of Mr. Riegel’s stock options that have not vested as of the Resignation Date will expire immediately on the Resignation Date. Furthermore, Mr. Riegel has agreed to additional terms and conditions as outlined in the Letter of Understanding, including (i) certain confidentiality obligations and (ii) certain non-compete and non-solicitation obligations during the period from October 1, 2012 to March 31, 2015.

Copies of the Letter of Understanding and the Company’s press release are attached hereto as Exhibits 99.1 and 99.2, respectively, and are incorporated herein by reference.

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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