UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2023 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF For the transition period from to Commission File Number: 001-37758 Moleculin Biotech, Inc. (Exact name of registrant as specified in its charter) Delaware 47-4671997 (State or Other Jurisdiction of (I.R.S. Emp ...