John Thomas O'Leary (February 12, 1929 – December 2, 1983) was an American football and basketball coach and college athletics administrator. He served as the head football coach at St. Mary of the Plains College in Dodge City, Kansas from 1960 to 1962, compiling a record of 8–18. O'Leary was also the athletic director at Colorado State University from 1974 to 1976 and the University of Central Florida (UCF) from 1976 to 1981. O'Leary died of a heart attack, on December 2, 1983, at the age of 54.