John O'Sullivan may refer to:
Sports John O'Sullivan (cricketer) (1918–1991), New Zealand cricketer John O'Sullivan (cyclist) (1933–2023), Australian cyclist John O'Sullivan (footballer, born 1993), Irish footballer for Shelbourne John O'Sullivan (footballer, born 2006), Irish footballer for Shamrock Rovers John O'Sullivan (rugby league) (1950–2018), New Zealand rugby league footballer John O'Sullivan (rugby union) (born 1980), Irish rugby union footballer John Lack O'Sullivan (1976–2002), Gaelic footballer and Australian rules footballer
Politics and government John O'Sullivan (Cork politician) (1901–1990), Irish Fine Gael Party politician, Senator, later TD for Cork South-West John O'Sullivan (Illinois politician), member of the Illinois House of Representatives John C. O'Sullivan (1841–?), politician in Ontario, Canada John M. O'Sullivan (1881–1948), Irish Cumann na nGaedhael/Fine Gael politician, TD, cabinet minister and academic
Other John O'Sullivan (columnist) (born 1942), British conservative columnist and editor John O'Sullivan (engineer), Australian astronomer and electrical engineer, and one of the inventors of Wi-Fi Sir John O'Sullivan (soldier) (1700–1760), Irish soldier, Quartermaster general to Prince Charles Edward Stewart during the Jacobite Rising of 1745 John Francis O'Sullivan (1850–1907), Irish-American awarded the Medal of Honor during the Indian Wars John L. O'Sullivan (1813–1895), journalist who popularized the phrase "Manifest Destiny"
See also John Sullivan (disambiguation)