Donald A. (Tony) Martin (born December 24, 1940) is an American set theorist and philosopher of mathematics at UCLA, where he is a member of the faculty of mathematics and philosophy.
Among Martin's most notable work are the proofs of analytic determinacy (from the existence of a measurable cardinal), Borel determinacy (from ZFC alone), the proof (with John R. Steel) of projective determinacy (from suitable large cardinal axioms), and his work on Martin's axiom. Martin measure on Turing degrees is also named after Martin.
Martin is a Harvard junior fellow. In 2014, he became a Fellow of the American Mathematical Society.