William George O'Brien (August 25, 1924 – May 8, 2005) was an American football player.
Born in Detroit, O'Brien attended University of Detroit Jesuit High School.
He played professional football in the National Football League as a halfback for the Detroit Lions.
He appeared in nine games for the Lions during the 1947 season.
This biographical article relating to an American football running back born in the 1920s is a stub.