William Fitch (born May 19, 1934 in Davenport, Iowa) is an American former NBA coach who has been successful in making teams playoff contenders throughout his coaching career. Before entering the professional ranks he coached college ball at the University of Minnesota, Bowling Green State University, the University of North Dakota, and his alma mater, Coe College. Fitch's teams twice qualified for the NCAA tournament.
Fitch was a former U.S. Marine Corps drill instructor, a fact that Larry Bird credited in his book Drive: The Story of My Life as an important reason for Bird's own strong work ethic.
During his 25-year pro coaching career Fitch repeatedly was hired in an attempt to improve failing teams. As of 2004 Fitch ranked fifth among all NBA coaches in all-time number of victories (with 944) but also ranked second in all-time losses (with 1,106) behind Lenny Wilkens. He was awarded as the NBA's Coach of the Year Award twice and he guided Bird, Kevin McHale, Robert Parish and the rest of the Boston Celtics to the 1981 NBA championship, defeating the Houston Rockets 4 games to 2 in the finals. From Boston, Fitch went on to coach the Rockets where he led a team featuring Hakeem Olajuwon and Ralph Sampson to the 1986 NBA Finals where they were defeated once again by Bird's Celtics, 4 games to 2, for the NBA championship.
Fitch also coached the Cleveland Cavaliers, New Jersey Nets and Los Angeles Clippers. During his first year with the Cavaliers, the team lost its first 15 games.