The 1980 Calder Cup Playoffs of the American Hockey League began on April 8, 1980. The playoff format was expanded from 6 to 8 teams. The eight teams that qualified played best-of-7 series for Division Semifinals and Division Finals. The division champions played a best-of-7 series for the Calder Cup. The Calder Cup Final ended on May 17, 1980 with the Hershey Bears defeating the New Brunswick Hawks four games to two to win the Calder Cup for the sixth time in team history.
After the 1979–80 AHL regular season, the top four teams from each division qualified for the playoffs. The New Haven Nighthawks finished the regular season with the best overall record.
In each round, the team that earned more points during the regular season receives home ice advantage, meaning they receive the "extra" game on home-ice if the series reaches the maximum number of games. There is no set series format due to arena scheduling conflicts and travel considerations.
Division Semifinals[]
Note 1: Home team is listed first.
Note 2: The number of overtime periods played (where applicable) is not indicated
Northern Division[]
(1) New Brunswick Hawks vs. (4) Adirondack Red Wings[]
April 8
New Brunswick Hawks
3 - 1
Adirondack Red Wings
April 9
New Brunswick Hawks
4 - 1
Adirondack Red Wings
April 11
Adirondack Red Wings
2 - 4
New Brunswick Hawks
April 13
Adirondack Red Wings
5 - 2
New Brunswick Hawks
April 14
New Brunswick Hawks
6 - 2
Adirondack Red Wings
New Brunswick won series 4 - 1
(2) Nova Scotia Voyageurs vs. (3) Maine Mariners[]
April 10
Nova Scotia Voyageurs
2 - 3
OT
Maine Mariners
April 12
Nova Scotia Voyageurs
3 - 2
Maine Mariners
April 15
Maine Mariners
7 - 0
Nova Scotia Voyageurs
April 17
Maine Mariners
6 - 5
OT
Nova Scotia Voyageurs
April 19
Nova Scotia Voyageurs
4 - 2
Maine Mariners
April 21
Maine Mariners
7 - 3
Nova Scotia Voyageurs
Maine won series 4 - 2
Southern Division[]
(1) New Haven Nighthawks vs. (4) Rochester Americans[]