Robert M. Wald (born June 29, 1947 in New York City) is a physicist who specializes in general relativity and the thermodynamics of black holes. He is the son of the mathematician and statistician Abraham Wald. Wald's parents died in a plane crash when he was three years old. He is the author of a graduate textbook, General Relativity. Wald is a professor at the Enrico Fermi Institute and the University of Chicago. Wald has taught undergraduate courses across a range of physics topics, and has been honored as a particularly effective teacher.
Wald has published over 100 research papers on general relativity and quantum field theory in curved spacetimes, many of which have been cited by hundreds of subsequent papers. He is a contributor to the framework of Algebraic Quantum Field Theory. In 1993, he described the Wald's entropy of a black hole, which is dependent simply on the area of the event horizon of the black hole.