Martin Hugh Michael O'Neill, OBE (born 1 March 1952) is an Northern Irish professional football manager and former player who played as a midfielder. His most recent appointment was as manager of Championship club Nottingham Forest but he was sacked on 28 June 2019 after five months in charge of the Championship outfit.
Starting his career in Northern Ireland, O'Neill moved to England where he spent most of his playing career with Nottingham Forest, with whom he won the European Cup twice, in 1979 and 1980. He was capped 64 times for the Northern Ireland national football team, also captaining the side at the 1982 World Cup.
O'Neill has managed Grantham Town, Wycombe Wanderers, Norwich City, Leicester City, Celtic, Aston Villa and Sunderland. He guided Leicester City to the Football League Cup final three times, winning twice. As Celtic manager between 2000 and 2005, he led that club to three Scottish Premier League titles and the 2003 UEFA Cup Final. After joining Aston Villa he achieved three consecutive sixth-place finishes in the English Premier League and guided them to the 2010 Football League Cup Final.