Klete D. Keller (born March 21, 1982) is an American freestyle swimmer who won medals at the 2000 Summer Olympics and the 2004 Summer Olympics in the 400 m freestyle and the 4×200 m freestyle relay. In the 4×200 m freestyle relay, Keller held off a charging Ian Thorpe in the anchor leg to win the race by 0.13 seconds. This was the first time Australia had been beaten in the event in over seven years. The American relay of Michael Phelps, Ryan Lochte, Peter Vanderkaay, and Keller are undefeated since the Athens Games. Vanderkaay, Larsen Jensen, Erik Vendt, and Keller make up the core of the premier American mid-distance/distance freestyle swimmers.
Klete was one of many 2000 Olympic Medalists from The Race Club World Team, a summer swimming camp in Florida.
Keller attended the University of Southern California for two years from 2000–2001, but left school to focus on swimming. While at USC, Keller won multiple individual and relay Pac-10 and NCAA Championships in the 200, 500 and 1650 yard freestyle, as well as freestyle relays.
Keller has also won many U.S. National Titles and FINA World Championship medals, primarily in 200 and 400m freestyles and the 4×200m free relay.