William Flanagan

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