Mary Knisely (born Schilly; May 29, 1959) is a retired middle- and long-distance runner from the United States. She set her personal best (8:42.84) in the women's 3000-meter run on 13 July 1987 at a meet in Nice. Knisely is a two-time US national champion in the 3000 m (1986 and 1987), and was the marathon national champion in 2001. She competed as a student at Concord High School.