Jack A. Gillespie (born October 1, 1947) is a retired professional basketball forward who played one season in the American Basketball Association (ABA) as a member of the New York Nets during the 1969–70 season.
He graduated from Great Falls High School in Great Falls, Montana, where he led the team to a Montana High School Basketball Championship in 1964. He attended Montana State University where he finished his college career as the school's all-time leader in rebounds (1,011) and points (1,543) along with two Big Sky Conference Player of the Year awards. Gellespie went on to be inducted into the Montana State Bobcats' Hall of Fame.
In 1999, Sports Illustrated ranked him forty-seventh in a list of Montana's 50 greatest athletes of all time. The Great Falls Tribune newspaper in 2014 listed him as one of the top four athletes to play high school basketball in the city.
- Nicholson, Ken (November 17, 1965). "Sweeney's Thoughts Turn to Moscow". Great Falls Tribune. p. 6. Retrieved June 19, 2018.
- "Hall of Fame: Jack Gillespie Class of 1970". msubobcats.com/. Montana State Bobcats. Retrieved 1 January 2014.
- "The 50 Greatest Sports Figures From Montana". Sports Illustrated. December 27, 1999. Retrieved June 19, 2018.
- Mansch, Scott (November 1, 2014). "Montana's greatest ball players: Wayne Estes died too young". Great Falls Tribune. Retrieved June 19, 2018.