Oscar Palmer Robertson (born November 24, 1938 in Charlotte, Tennessee), nicknamed "The Big O", is a former American NBA player with the Cincinnati Royals and the Milwaukee Bucks. The 6-foot-5, 220-pound Robertson played the guard position, and was a twelve-time All-Star, eleven-time member of the All-NBA Team, and one-time winner of the MVP award in fourteen professional seasons. He is the only player in NBA history to average a triple-double for an entire season, and he is regarded as one of the best and most versatile NBA players of all time. He was a key player on the team which brought the Bucks their only NBA championship in the 1970-71 NBA season. However, his playing career, especially during high school and college, was plagued by racism.

For his outstanding achievements, Robertson was inducted into the Basketball Hall of Fame in 1980, and 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.

Robertson was also an integral part of the Oscar Robertson suit of 1970. The landmark NBA antitrust suit, named after the then-president of the NBA Players' Association, led to an extensive reform of the league's strict free agency and draft rules and, subsequently, to higher salaries for all players.