The 1983–84 OHL season was the fourth season of the Ontario Hockey League. Fifteen teams each played 70 games. The Ottawa 67's won the J. Ross Robertson Cup, defeating the Kitchener Rangers.
Peterborough Petes defeat Cornwall Royals 3–0
Oshawa Generals defeat Belleville Bulls 3–0
Sault Ste. Marie Greyhounds defeat Windsor Spitfires 3–0
London Knights defeat North Bay Centennials 3–1
Ottawa 67's defeat Oshawa Generals 4–0
Toronto Marlboros defeat Peterborough Petes 4–1
Kitchener Rangers defeat London Knights 4–0
Sault Ste. Marie Greyhounds defeat Brantford Alexanders 4–2
Ottawa 67's defeat Toronto Marlboros 4–0
Kitchener Rangers defeat Sault Ste. Marie Greyhounds 4–3
Ottawa 67's defeat Kitchener Rangers 4–1