John J. or John Joseph O'Neill may refer to:
John Joseph O'Neill (journalist) (1889–1953), winner of the Pulitzer Prize for Reporting John J. O'Neill (American politician) (John Joseph O'Neill, 1846–1898), Missouri congressman John Joseph O'Neill (British politician) (1888–1953), Liberal Party politician in England, member of parliament for Lancaster 1923–1924 John Johnston O'Neill (1886–1966), Canadian geologist and academic John O'Neill (guitarist) (John Joseph O'Neill, born 1957), Northern Irish guitarist of rock band The Undertones John O'Neill (footballer, born 1974) (John Joseph O'Neill), former Scottish football player with Queen of the South and former manager of Stirling Albion Jonjo O'Neill (jockey) (John Joseph O'Neill, born 1952), Irish racehorse trainer and jockey Jack O'Neill (baseball) (John Joseph O'Neill, 1873–1935), catcher in Major League Baseball
See also John O'Neill (disambiguation)