Harold Jack Swarthout (February 23, 1920 – October 1, 2005) was an American college football player, coach, and administrator. He served as head football coach and athletic director at his alma mater, the University of Montana, from 1967 through 1975. Swarthout compiled an overall record of 51–41–1 (.554), winning Big Sky Conference championships in 1969 and 1970.