William, Will, Bill, or Billy Irwin may refer to:
Law and politics William W. Irvin or Irwin (1778–1842), American politician in Ohio William W. Irwin (1803–1856), American politician in Pittsburgh, Pennsylvania William Irwin (California politician) (1827–1886), American politician in California William Irwin (Unionist politician) (born 1956), Unionist politician in Northern Ireland Bill Irwin (politician), American politician in Missouri
Sports Bill Irwin (baseball) (1859–1933), American baseball player Billy Irwin (Australian rules footballer) (1884–1946), Australian footballer Bill Irwin (skier) (1920–2013), Canadian skier Bill Irwin (footballer) (born 1951), Northern Irish footballer Bill Irwin (wrestler) (born 1954), American professional wrestler Billy Irwin (boxer) (born 1968), Canadian boxer
Others Will Irwin (1873–1948), American journalist William Andrew Irwin (1884–1967), Canadian theologian William Roy Irwin (1898–1969), Canadian-born World War I flying ace William Arthur Irwin (1898–1999), Canadian journalist and diplomat William C. K. Irwin (1907–1998), American pianist, conductor, and songwriter William G. Irwin (1843–1914), capitalist and sugar planter in the Kingdom of Hawai'i William Glanton Irwin (1866–1943), American banker and co-founder of the Cummins Engine Company Bill Irwin (priest) (1928–2004), Canadian priest Bill Irwin (born 1950), American actor and clown William Irwin (philosopher) (born 1970), American professor of philosophy
See also Bill Erwin (1914–2010), American character actor Billie Irwin (1942–2025), New Zealand netball player William Irvin (disambiguation) William Irvine (disambiguation) William Irving (disambiguation) William Irwin Thompson (born 1938), social philosopher, cultural critic and poet Irwin (surname)