Forrest Clare "Phog" Allen (November 18, 1885 – September 16, 1974) was an American basketball and baseball player, coach of American football, basketball, and baseball, college athletics administrator, and osteopathic physician. Known as the "Father of Basketball Coaching," he served as the head basketball coach at Baker University (1905–1908), the University of Kansas (1907–1909, 1919–1956), Haskell Institute—now Haskell Indian Nations University (1908–1909), and Warrensburg Teachers College—now the University of Central Missouri (1912–1919), compiling a career college basketball record of 746–264. In his 39 seasons at the helm of the Kansas Jayhawks men's basketball program, his teams won 24 conference championships and three national titles. The Helms Athletic Foundation retroactively recognized Allen's 1921–22 and 1922–23 Kansas teams as national champions. Allen's 1951–52 squad won the 1952 NCAA Tournament and his Jayhawks were runners-up in the NCAA Tournament in 1940 and 1953. His 590 wins are the most of any coach in the storied history of the Kansas basketball program.
Allen attended the University of Kansas, having already acquired the nickname "Phog" for the distinctive foghorn voice he had as a baseball umpire. He lettered in baseball and basketball, the latter under James Naismith, the inventor of the game. Allen served as the head football coach at Warrensburg Teachers College from 1912 to 1917 and at Kansas for one season in 1920, amassing a career college football record of 34–19–3. He also coached baseball at Kansas for two seasons, in 1941 and 1942, tallying a mark of 6–17–1, and was the university's athletic director from 1919 to 1937. Allen was inducted into the Naismith Memorial Basketball Hall of Fame with the inaugural class of 1959. The home basketball arena at the University of Kansas, Allen Fieldhouse, was named in his honor when it opened in 1955.
He is also known as Forrest Clare "Phog" Allen.