Stuart Alan Geman (born March 23, 1949) is an American mathematician, known for influential contributions to computer vision, statistics, probability theory, machine learning, and the neurosciences.

He was educated at the University of Michigan (B.S., Physics, 1971), Dartmouth Medical College (MS, Neurophysiology, 1973), and the Massachusetts Institute of Technology (Ph.D, Applied Mathematics, 1977).

Since 1977, he has been a member of the faculty at Brown University, where he has worked in the Pattern Theory group, and is currently the James Manning Professor of Applied Mathematics.

He has received many honors and awards, including selection as a Presidential Young Investigator and as an ISI Highly Cited researcher.

Particularly notable works include: the development of the Gibbs sampler, proof of convergence of simulated annealing,[8][9] foundational contributions to the Markov random field ("graphical model") approach to inference in vision and machine learning,[3][10] and work on the compositional foundations of vision and cognition.