Griffon (GFF) 10-K 2018 FY Annual report

EXHIBIT 23

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We have issued our report dated November 16, 2018 with respect to the consolidated financial statements, schedule and internal control over financial reporting included in the Annual Report of Griffon Corporation on Form 10-K for the year ended September 30, 2018. We consent to the incorporation by reference of said report in the Registration Statements of Griffon Corporation’s Form S-3 (File No. 333-224727), Forms S-4 (File No. 333-222156; File No. 333-211962 and File No. 333-195647) and Forms S-8 (File No. 333-222844; File No. 333-209222; File No. 333-193691; File No. 333-172162; File No. 333-157190; File No. 333-149811; File No. 333- 133833; and File No. 333-131737).

/s/ GRANT THORNTON LLP

New York, New York

November 16, 2018