William O'Neill

• Bill O'Neill (1880–1920), baseball player
• Bill O'Neill (born 1981), professional ten-pin bowler
• Billy O'Neill (1878–1955), Welsh rugby player
• Buckey O'Neill (1860–1898), Old West sheriff and U.S. Army officer killed at the Battle of San Juan Hill
• C. William O'Neill (1916–1978), Governor of Ohio
• William O'Neil (born 1933), entrepreneur and stockbroker who founded the newspaper Investor's Business Daily
• William O'Neill, 1st Baron O'Neill (1813–1883), Anglo-Irish hereditary peer, clergyman and musical composer
• William O'Neill (1930–2007), Governor of Connecticut in the 1980s and early 1990s
• William O'Neill (1848–?), American soldier in the Indian Wars
• William O'Neill (born 1947), appellate judge and 2008 candidate for U.S. Representative from Ohio's 14th congressional district
• Willie O'Neill (1940–2011), Scottish footballer (Celtic FC)
• Willie O'Neill , see List of All-Ireland Senior Hurling Championship medal winners
• Willie O'Neill , see Gerald McCarthy
• Willie O'Neill , see 1938 FIFA World Cup qualification

See also

• Bill O'Neal (born 1942), American historian
• Bill O'Neil, former member of the Ohio House of Representatives
• Billy O'Neil, fictional footballer in Dream Team