The 1979–80 OMJHL season was the sixth season of the Ontario Major Junior Hockey League. The OMJHL inaugurates the Bobby Smith Trophy, named after Bobby Smith, awarded to the scholastic player of the year. Twelve teams each played 68 games. The Peterborough Petes won the J. Ross Robertson Cup, defeating the Windsor Spitfires.
Regular season
Final standings Note: GP = Games played; W = Wins; L = Losses; T = Ties; GF = Goals for; GA = Goals against; PTS = Points; x = clinched playoff berth; y = clinched first round bye; z = clinched division title & first round bye Leyden Division Emms Division Scoring leaders ==Playoffs==
Playoffs
Division quarter-finals Leyden Division (4) Kingston Canadians vs. (5) Sudbury Wolves Emms Division (4) Niagara Falls Flyers vs. (5) London Knights Division semi-finals Leyden Division (1) Peterborough Petes vs. (5) Sudbury Wolves (2) Ottawa 67's vs. (3) Oshawa Generals Emms Division (1) Windsor Spitfires vs. (4) Niagara Falls Flyers (2)Toronto Marlboros vs. (3) Brantford Alexanders Division finals Leyden Division (1) Peterborough Petes vs. (2) Ottawa 67's Emms Division (1) Windsor Spitfires vs. (3) Brantford Alexanders J. Ross Robertson Cup (L1) Peterborough Petes vs. (E1) Windsor Spitfires ==Awards==