John O'Neill
John O'Neill may refer to:
Music
- John O'Neill (guitarist), Northern Irish guitarist of rock band The Undertones
- John O'Neill (musician, born 1926), British singer, whistler, and trumpeter
Politics
- John O'Neill (Canadian politician), Liberal politician in Ontario, Canada
- John O'Neill (congressman), U.S. Representative from Ohio and state senator
- John O'Neill (Fenian), member of the Irish Republican Brotherhood
- John O'Neill (Irish senator), Irish Cumann na nGaedheal senator in 1925
- John O'Neill (philosopher), political philosopher, professor of political economy at the University of Manchester
- John O'Neill (political activist), fervent opponent of John Kerry and a leader of the groups Swift Vets and POWs for Truth
- John O'Neill (Wisconsin politician), Wisconsin state assemblyman
- John O'Neill, 1st Viscount O'Neill, Irish politician
- John O'Neill, 3rd Viscount O'Neill, Irish Tory politician
- John A. O'Neill, American steel engraver and mayor of Hoboken, New Jersey
- John J. O'Neill (American politician), Missouri congressman
- John Joseph O'Neill (British politician), Liberal Party politician in England, member of parliament for Lancaster 1923–1924
- John Raymond O'Neill, Conservative member of the Canadian House of Commons
- St John O'Neill represented Randalstown in the Irish House of Commons
Sports
- John O'Neill (Australian rules footballer), Geelong player during the 1950s
- John O'Neill (baseball), baseball player
- John O'Neill (field hockey), American former field hockey player
- John O'Neill (footballer, born 1935), Republic of Ireland and Preston North End player
- John O'Neill (footballer, born 1958), Northern Ireland player
- John O'Neill (footballer, born 1974), former Scottish football player with Queen of the South and former manager of Stirling Albion
- John O'Neill (rugby league), Australian rugby league footballer and coach
- John O'Neill (rugby union, born 1973), Irish rugby union player
- John O'Neill (rugby union, born 1932), Australian rugby union player
- John O'Neill (Limerick hurler), from the 1994 All-Ireland Senior Hurling Championship final
- John O'Neill (Tipperary hurler), Irish hurler
- John O'Neill (runner), American steeplechase runner, 2nd at the 1925 USA Outdoor Track and Field Championships
Other
- John O'Neill, architect who oversaw the completion of St Peter's Cathedral, Belfast
- John O'Neill (businessman), CEO of the Australian Rugby Union and former head of Football Federation Australia
- John O'Neill (editor), founding editor of Black Gate (magazine)
- John O'Neill (lighthouse keeper), American military officer and lighthouse keeper
- John O'Neill (poet), Irish shoemaker poet and playwright
- John O'Neill (VC), Scottish recipient of the Victoria Cross during the First World War
- John O'Neill (video game designer), experimental art video game designer
- John O'Neill, 3rd Earl of Tyrone, the son of Hugh O'Neill
- John Johnston O'Neill, Canadian geologist and academic
- John Joseph O'Neill (journalist), winner of the Pulitzer Prize for Reporting
- John P. O'Neill, former FBI agent and head of security at the World Trade Center at the time of the September 11, 2001 attacks
- John S. O'Neill, British molecular biologist
- John Michael O'Neill, Canadian Roman Catholic bishop
- John O'Neill (sociologist), Canadian sociologist, phenomenologist, and social theorist