William Devlin may refer to:
- William Devlin (actor) (1911–1987), Scottish actor
- William Devlin (footballer, born 1893), English footballer (Stockport County, Cardiff City, Newport County)
- William Devlin (footballer, born 1899), Scottish footballer (Cowdenbeath FC, Huddersfield Town, Liverpool FC, Heart of Midlothian)
- William Devlin (footballer, born 1931), Scottish footballer (Carlisle United)
- William J. Devlin (1875–1938), American Jesuit and academic administrator
- Bill Devlin (born c.1947), American politician (North Dakota representative)
- Billy Devlin, swimmer from Northern Ireland