Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q (State or other jurisdiction of incorporation or organization) FOR THE QUARTERLY PERIOD ENDED SEPTEMBER 30, 2026 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO COMMISSION FILE NUMBER: 001-33097 GLADSTONE COMMERCIAL CORPORATION (Mark One) (Exact name of registrant as specified in its charter) ☒ QUARTERLY REPORT PURSUANT TO SECTION ...