Michael R. Douglas (born November 19, 1961) is an American theoretical physicist, best known for his work in string theory and mathematical physics. Douglas is best known for the development of matrix models (the first nonperturbative formulations of string theory), for his work on Dirichlet branes and on noncommutative geometry in string theory, and for the development of the statistical approach to string phenomenology. He was on the team (led by Gerald J. Sussman) that built the Digital Orrery, a special-purpose computer for computations in celestial mechanics, and maintains an active interest in computer science. He is also very active in organizing schools and workshops, for example at Les Houches, Cargese, and the KITP Santa Barbara. Douglas received the 2000 Sackler Prize in theoretical physics. In 2012 he became a fellow of the American Mathematical Society. He has a long association with the Institut des Hautes Études Scientifiques, and as chairman and President of the Friends of IHES from 2013 to 2021.