Joseph Donald Barnett (born January 10, 1944) is an American retired college basketball coach. He was a former head basketball coach at several Division I institutions, the most high-profile being Virginia Commonwealth University, where his most notable win consisted of a buzzer-beater NCAA Tournament win over Jim Calhoun's Northeastern Huskies. He is also well known for being a mentor of Tubby Smith, the current head coach at High Point University. Most notably, Barnett taught Smith the philosophy of ball-line defense, which is a strategy that requires all defenders to stay between the line of the ball and the baseline. He was most recently the head coach and athletic director at Division II Hawaii Pacific.