Marvin L. Cohen (born Montreal on March 3, 1935) is a Canadian-born American physicist. He is a professor of condensed matter physics and materials science at the University of California, Berkeley. Nobel laureate Robert B. Laughlin studied under John D. Joannopoulos, a student of Cohen's.
Cohen received his PhD from the University of Chicago in 1964, under Professor Jim Phillips. He has received the Oliver E. Buckley Prize in 1979, the Julius Edgar Lilienfeld Prize in 1994, and the National Medal of Science in 2001. He is a member of the National Academy of Sciences, and in 2005, he served as President of the American Physical Society. He is noted for studies of materials.