William D. Ridley (February 2, 1934 – September 28, 2019) was an American college basketball player.

[1][2] He chose to play for coach Harry Combes at Illinois as a part of a strong recruiting class that also included in-state players Bruce Brothers and twins Phil and Paul Judson.

[3] He moved into the starting lineup in his sophomore season, raising his scoring average to 15.2 points per game and was named third-team All-Big Ten Conference by the United Press International (UPI), who also named him to their national "Small-America" team of the top players under 5 ft 10 in (1.78 m).

[4][5] In Ridley's senior season, the Illini started a potent scoring lineup with Brother, Paul Judson and George Bon Salle in the frontcourt with Ridley running the attack from the perimeter.

[8] Ridley finished the year averaging 15.3 points per game and at the close of the season was named All-Big Ten and as a third-team All-American by both the Associated Press (AP) and UPI.