Stephen Collins (born 21 July 1964) is an Irish former professional boxer who competed from 1986 to 1997. Known as "The Celtic Warrior", Collins is the most successful Irish boxer in professional boxing history, having held the WBO middleweight and super-middleweight titles. Collins' first professional twenty fights all took place in the United States. In 1988 he won the Irish middleweight title, and the regional American USBA middleweight title the following year, defending the latter successfully in Atlantic City and Las Vegas. In his first two world championship challenges, both for the WBA middleweight title, Collins lost split decisions to Mike McCallum in 1990 and Reggie Johnson in 1992. He also challenged unsuccessfully for the European middleweight title in 1992, losing a split decision to Sumbu Kalambay in Italy. It was not until Collins reached his early 30s that he fulfilled his potential, becoming WBO middleweight champion in his third world title attempt in 1994. The next year, he won the WBO super-middleweight title and defended it seven times before retiring from the sport. Having competed against the best boxers on both sides of the Atlantic, Collins tends to be linked more to an era in the UK during which there was a notable rivalry between British boxers Chris Eubank and Nigel Benn, both of whom he fought and defeated twice.