Oscar Palmer Robertson (born November 24, 1938), nicknamed "The Big O", is an American retired National Basketball Association player who played for the Cincinnati Royals and Milwaukee Bucks. The 6 ft 5 in (1.96 m), 220 lb (100 kg) Robertson played the point guard and shooting guard positions, and was a 12-time All-Star, 11-time member of the All-NBA Team, and one-time winner of the MVP award in 14 professional seasons. He is the only player in NBA history to average a triple-double for a season. He was a key player on the team which brought the Bucks their only NBA title in the 1970–71 NBA season. His playing career, especially during high school and college, was plagued by racism.

Robertson is a two-time Naismith Memorial Basketball Hall of Fame inductee, having been inducted in 1980 for his individual career, and in 2010 as a member of the 1960 United States men's Olympic basketball team and president of the National Basketball Players Association. He also was voted one of the 50 Greatest Players in NBA History in 1996. The United States Basketball Writers Association renamed their College Player of the Year Award the Oscar Robertson Trophy in his honor in 1998, and he was one of five people chosen to represent the inaugural National Collegiate Basketball Hall of Fame class in 2006. He was ranked as the 36th best American athlete of the 20th century by ESPN.