William Samuel Frieder (born March 3, 1942) is a former basketball coach at Michigan (1981–1989) and Arizona State (1989–1997).

Just before the 1989 NCAA tournament, Frieder announced that he would leave Michigan for Arizona State at the end of the season.

Michigan athletic director Bo Schembechler ordered Frieder to leave immediately, and named top assistant Steve Fisher as the interim coach for the tournament.

Frieder resigned from Arizona State in 1997 following a point-shaving scandal that involved games from the school’s 1994 season.

During the 1990s, Frieder and Lute Olson, then coach of the Arizona Wildcats, participated in a series of television commercials together for Bank One.