Exhibit 5

ATTORNEYS AT LAW   100 North Tampa Street, Suite 2700 Tampa, FL 33602-5810 P.O. Box 3391 Tampa, FL 33601-3391 813.229.2300 TEL 813.221.4210 FAX www.foley.com   CLIENT/MATTER NUMBER 106551-0103

June 9, 2026

Ladies and Gentlemen:

We have acted as counsel to Innovative Industrial Properties, Inc., a Maryland corporation (the “Company”), in connection with the preparation of a Registration Statement on Form S-8 (the “Registration Statement”) to be filed with the Securities and Exchange Commission on or about June 9, 2026, under the Securities Act of 1933, as amended (the “Securities Act”), registering 1,250,000 shares of the Company’s common stock, $0.001 par value (the “Shares”), issuable pursuant to the Innovative Industrial Properties, Inc. 2026 Omnibus Incentive Plan (the “Plan”).

As counsel to the Company, we have examined originals or copies, certified or otherwise identified to our satisfaction, of such documents, corporate records, certificates of public officials and other instruments as we have deemed necessary for the purposes of rendering this opinion, including but not limited to the Plan, the Registration Statement, the charter of the Company and the Bylaws of the Company, and we are familiar with the proceedings taken and proposed to be taken by the Company in connection with the authorization, issuance and sale of the Shares. In our examination, we have assumed the genuineness of all signatures, the legal capacity and competency of all natural persons, the authenticity of all documents submitted to us as originals and the conformity to original documents of all documents submitted to us as copies. We have also assumed the accuracy of all other information provided to us by the Company during the course of our investigations, on which we have relied in issuing the opinion expressed below.

For the purpose of the opinion rendered below, we have assumed that in connection with the issuance of the Shares under the Plan, the Company will receive consideration in an amount not less than the aggregate par value of the Shares covered by each such issuance, and that any certificates representing the Shares that are covered by the Registration Statement conform to the Form of Common Stock Certificate included as Exhibit 4.4 to the Registration Statement.

It is understood that this opinion is to be used only in connection with the offer and sale of the Shares while the Registration Statement is effective.

We express no opinion herein as to the laws of any state or jurisdiction other than the Maryland General Corporation Law and the federal laws of the United States of America.

Based upon the foregoing, we are of the opinion that the Shares, when issued by the Company pursuant to the terms and conditions of the Plan, will be validly issued, fully paid and nonassessable and that the issuance of such Shares has been registered under the Securities Act.

AUSTIN | BOSTON | BRUSSELS | CHICAGO | DALLAS | DENVER | DETROIT | HOUSTON | JACKSONVILLE | LOS ANGELES
MADISON | MEXICO CITY | MIAMI | MILWAUKEE | NASHVILLE | NEW YORK | ORLANDO | RALEIGH | SACRAMENTO |
SALT LAKE CITY | SAN DIEGO | SAN FRANCISCO | SILICON VALLEY | TALLAHASSEE | TAMPA | TOKYO | WASHINGTON, D.C.

June 9, 2026
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We consent to the use of this opinion as an exhibit to the Registration Statement. In giving our consent, we do not admit that we are “experts” within the meaning of Section 11 of the Securities Act or within the category of persons whose consent is required by Section 7 of the Securities Act.