James O. Dennis (born 25 February 1976) is an American discus thrower. His personal best throw is 63.55 metres, achieved in June 2008 in Chula Vista, California.
Dennis was a two-time All-American for the Louisville Cardinals track and field team, placing 4th at the 1997 NCAA Division I Outdoor Track and Field Championships.
Dennis remains an active Masters athlete, winning the 2018 World Masters Athletics Championships and the 2024 World Masters Athletics Championships, among other championships.