Mary J. Gregor (January 1, 1928 – October 31, 1994) was an American author, translator, and professor. She was a Kant scholar and Professor Emeritus of Philosophy at San Diego State University, best known for translating the works of the German philosopher Immanuel Kant.
Allen W. Wood has recognized her translations as characterized "not only by meticulous linguistic accuracy and scholarly erudition but also by an unfailing sense of style and an uncanny ability to render Kant's meaning into readable and even elegant English".