William Flanagan may refer to: William Flanagan (composer) (1923–1969), American composer William Flanagan (American football) (1901–1975), professional football player William Flanagan (politician) (1871–1944), British Member of Parliament for Manchester Clayton, 1931–1935 William J. Flanagan Jr. (born 1943), U.S. Navy admiral William A. Flanagan (born 1980), former mayor of Fall River, Massachusetts