Derek Warren Isaman (born April 23, 1967) is an American former professional boxer.
Isaman played college football for the Ohio State Buckeyes, where he was the starting inside linebacker.
Isaman was the 1988 National Golden Gloves Heavyweight champion, he decisioned James Johnson in the quarterfinals, Tommy Morrison in the semifinals, and Robert Hargrove in the finals. He also lost a points decision to Mike Tyson in a prior National Golden Gloves semi-final. He was the only boxer to fight Tyson and not get knocked out.
Isaman turned pro in 1990 and won his first 12 fights, before losing a rematch to Marion Wilson in 1992. He retired in 1994 after a three fight win streak.