Ralph E. "Buckshot" O'Brien (April 8, 1928 – August 22, 2018) was an American professional basketball player. A 5'9" point guard from Butler University, O'Brien played two seasons (1951–1953) in the National Basketball Association as a member of the Indianapolis Olympians and Baltimore Bullets. He averaged 7.1 points per game in his NBA career. O'Brien was the last Butler product to appear in an NBA game for more than a half-century, before the 2010 arrival of Gordon Hayward.