1989–90 OHL season

The Oshawa Generals won the J. Ross Robertson Cup, defeating the Kitchener Rangers.

The Guelph Platers relocated to the city of Owen Sound during the off-season as the ownership group, the Holody family, could not get a new arena built.

The club previously played as the Kingston Canadians from 1973 to 1988 before being renamed as the Raiders for the 1988-89 season.

The Windsor Compuware Spitfires were sold by Peter Karmanos to local construction magnate Steve Riolo during the off-season, and reverted to their original team name, the Windsor Spitfires.

Note: GP = Games played; W = Wins; L = Losses; T = Ties; GF = Goals for; GA = Goals against; PTS = Points; x = clinched playoff berth; y = clinched division title [1]