William Henry Blair Jr. (born May 17, 1942[1]) is an American former basketball coach and player.

After three middling seasons, he led them to a conference championship in 1976 that saw then go to the Elite Eight in the NCAA Tournament.

Blair then worked twenty seasons in the National Basketball Association, beginning in New Jersey with the New Jersey Nets, and continuing to the Chicago Bulls, under Kevin Loughery, helping to draft Michael Jordan.

He then moved to the Washington Bullets under Wes Unseld, and next the Indiana Pacers under Larry Brown—coaching spectacular teams with Reggie Miller at the helm.

In 1993, he became the head coach of the Minnesota Timberwolves, then returned to the Pacers, and finally finished his career under Randy Whitman at the Cleveland Cavaliers.