William, Billy or Bill O'Neill may refer to:
Politics Bill O'Neill (Ohio politician), former member of the Ohio House of Representatives Bill O'Neill (New Mexico politician) (1956–2025), member of the New Mexico Senate C. William O'Neill (1916–1978), governor of Ohio William O'Neill (Ohio judge) (born 1947), appellate judge and 2008 candidate for U.S. Representative from Ohio's 14th congressional district William A. O'Neill (1930–2007), governor of Connecticut, 1980–1991 William G. O'Neill (1921–1996), member of the Florida House of Representatives William P. O'Neill (1874–1955), lieutenant governor of Indiana
Sports Bill O'Neill (American football) (1910–2000), American football player Bill O'Neill (baseball) (1880–1920), American baseball player Bill O'Neill (bowler) (born 1981), American professional ten-pin bowler Bill O'Neill (bowls) (1909–?), New Zealand lawn bowler Billy O'Neill (rugby) (1878–1955), Welsh rugby player William O'Neill (rugby union), Irish rugby union player Bill O'Neill (ice hockey) (born 1956), American college men's ice hockey coach Billy O'Neill (dual player) (1929–2015), Irish former Gaelic football and hurler Billy O'Neill (footballer) (born 1919), Irish footballer Willie O'Neill (footballer, born 1940) (1940–2011), Scottish footballer (Celtic FC) Willie O'Neill (Wexford hurler) (born 1945), Irish hurler Willie O'Neill (Cork hurler) (1876–1963), Irish hurler and Gaelic footballer Willie O'Neill (Irish footballer) (1916–1978), Irish international footballer
Others Bill O'Neill (media) (born 1936), News Corporation executive Buckey O'Neill (1860–1898), Old West sheriff and U.S. Army officer killed at the Battle of San Juan Hill William F. O'Neil, founder of General Tire and Rubber Company William O'Neill, 1st Baron O'Neill (1813–1883), Anglo-Irish hereditary peer, clergyman and musical composer William O'Neill (Medal of Honor) (c. 1848–?), American soldier in the Indian Wars
See also William O'Neil (disambiguation) Will O'Neill (disambiguation) Bill O'Neal, American historian; see Bibliography of Wyoming history Billy O'Neil, fictional footballer in Dream Team William O'Neal (disambiguation)