Exhibit 5.1

April 29, 2019

Thor Industries, Inc.

601 East Beardsley Avenue

Elkhart, Indiana 46514-3305

Ladies and Gentlemen:

We are acting as special counsel to Thor Industries Inc., a Delaware corporation (the “Company”), in connection with the preparation of the Registration Statement on Form S-3 (such Registration Statement, as amended or supplemented, is hereinafter referred to as the “Registration Statement”) filed by the Company with the Securities and Exchange Commission (the “Commission”) on April 29, 2019 under the Securities Act of 1933, as amended (the “Securities Act”). The Registration Statement relates to the sale from time to time, pursuant to Rule 415 of the General Rules and Regulations promulgated under the Securities Act, of 2,256,492 shares of Common Stock, par value $0.10 per share (the “Shares”), of the Company to be sold by the selling stockholders named in the Registration Statement (the “Selling Stockholders”).

In that connection, we have examined originals, or copies certified or otherwise identified to our satisfaction, of such documents, corporate records and other instruments as we have deemed necessary for the purposes of this opinion, including (i) the Amended and Restated Certificate of Incorporation, as amended, as certified by the Secretary of State of the State of Delaware on April 26, 2019, (ii) the Amended and Restated By-Laws of the Company, as amended, as certified by an authorized officer of the Company (iii) minutes and records of the corporate proceedings of the Company, (iv) the Registration Statement and the exhibits thereto and (v) an officer’s certificate of the Company executed for our benefit and of even date hereof.

For purposes of this opinion, we have assumed the authenticity of all documents submitted to us as originals, the conformity to the originals of all documents submitted to us as copies and the authenticity of the originals of all documents submitted to us as copies. We have also assumed the legal capacity of all natural persons, the genuineness of the signatures of persons signing all documents in connection with which this opinion is rendered, the authority of such persons signing on behalf of the parties thereto other than the Company and the due authorization, execution and delivery of all documents by the parties thereto other than the Company. We have not independently established or verified any facts relevant to the opinion expressed herein, but have relied upon statements and representations of officers and other representatives of the Company and others.

We have also assumed that:

(i) the Registration Statement and any amendments thereto (including post-effective amendments) will be effective and will comply with all applicable laws at the time the Shares are offered or sold as contemplated by the Registration Statement;

Thor Industries, Inc.

April 29, 2019

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(ii) a prospectus supplement or term sheet (“Prospectus Supplement”), to the extent required by applicable law, will have been prepared and filed with the Commission describing the Shares offered thereby and will comply with all applicable laws; and

(iii) all Shares will be offered and sold in compliance with applicable federal and state securities laws and in the manner stated in the Registration Statement and the appropriate Prospectus Supplement.

Based upon and subject to the foregoing qualifications, assumptions and limitations and the further limitations set forth below, we are of the opinion that the Shares have been duly authorized and are validly issued, fully paid and non-assessable.

Our opinion expressed above is subject to the qualification that we express no opinion as to the applicability of, compliance with, or effect of any laws except the General Corporation Law of the State of Delaware (including the statutory provisions, all applicable provisions of the Delaware constitution and reported judicial decisions interpreting the foregoing).

We hereby consent to the filing of this opinion with the Commission as Exhibit 5.1 to the Registration Statement. We also consent to the reference to our firm under the heading “Legal Matters” in the Registration Statement. In giving this consent, we do not thereby admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Commission.

We do not find it necessary for the purposes of this opinion, and accordingly we do not purport to cover herein, the application of the securities or “Blue Sky” laws of the various states to the issuance and sale of the Shares.

This opinion is limited to the specific issues addressed herein, and no opinion may be inferred or implied beyond that expressly stated herein. We assume no obligation to revise or supplement this opinion after the date of effectiveness should the General Corporation Law of the State of Delaware be changed by legislative action, judicial decision or otherwise after the date hereof.

This opinion is furnished to you in connection with the filing of the Registration Statement in accordance with the requirements of Item 601(b)(5) of Regulation S-K under the Securities Act.

Very truly yours,

/s/ Ice Miller LLP