George Francis Denton Duff FRSC (July 29, 1926 – March 2, 2001) was a Canadian mathematician who did research in partial differential equations and wave phenomena. He took an interest in harnessing the extraordinarily large tides in the Bay of Fundy for generating electricity. Duff was a PhD student of Solomon Lefschetz at Princeton University. He became a professor at the University of Toronto in 1952. There, he supervised the Ph.D. theses of 13 students and served as chair of the Mathematics Department from 1968 to 1975.