Michael, Mike, or Mikey O'Neill may refer to:
Arts and entertainment Mike O'Neill (costume designer) (1945-2018), British-Irish costume designer Michael O'Neill (actor) (born 1951), American actor Michael O'Neill (academic) (1953–2018), English poet Mike O'Neill (musician) (born 1970), Canadian singer-songwriter
Law and politics Michael C. O'Neill (1888–1943), American politician Michael O'Neill (politician) (1909–1976), Irish politician Michael O'Neill (diplomat) (born 1967), British diplomat
Sports Mike O'Neill (baseball) (1877–1959), Irish-born American baseball player Mike O'Neill (basketball) (born 1928), American basketball player Mike O'Neill (lacrosse) (fl. 1970s), American lacrosse player Mike O'Neill (rugby league) (born 1960), English rugby league footballer Mike O'Neill (ice hockey) (born 1967), Canadian ice hockey goaltender Michael O'Neill (footballer) (born 1969), Northern Irish football player and manager Mikey O'Neill (footballer) (born 2004), English footballer
Others Michael E. O'Neill (born 1946), American business executive Michael O'Neill (educator), American non-profit management educator
See also Michael O'Neal (born 1951), American lawyer and politician Mickey O'Neil (1900–1964), American baseball player