Donald Lee O'Riley (March 12, 1945 – May 2, 1997) was a Major League Baseball pitcher who played for two seasons. He pitched in 18 games for the Kansas City Royals during the inaugural 1969 season and nine games during the 1970 season. He was traded along with Pat Kelly from the Royals to the Chicago White Sox for Gail Hopkins and John Matias on October 13, 1970.
O'Riley died at age 52 after being fatally shot during a convenience store robbery.