Harold Roy Ballin (October 16, 1893 – December 25, 1979) was an American football player and coach. He played at the tackle position for Princeton University from 1912 to 1914 and was a consensus first-team All-American in both 1913 and 1914. Ballin served as the head football coach at Duquesne University from 1922 to 1923, compiling a record of 4–12. He was inducted into the College Football Hall of Fame as a player in 1973.