|Dates April 3–May 25, 1991|
Champions Pittsburgh Penguins
Runner-up Minnesota North Stars
|Semifinalists Boston Bruins Edmonton Oilers|
The 1991 Stanley Cup Playoffs for the National Hockey League (NHL) championship began on April 3, 1991, following the 1990–91 regular season. The sixteen teams that qualified, from the top four teams of the four divisions, played best-of-seven series with re-seeding after the division finals. The Conference Champions played a best-of-seven series for the Stanley Cup.
- Playoff seeds
- Adams Division
- Patrick Division
- Norris Division
- Smythe Division
- S3 Edmonton Oilers vs N4 Minnesota North Stars
This was the first of 25 consecutive years in which the Detroit Red Wings have qualified for the Stanley Cup Playoffs. Their streak is tied for the third longest in NHL history, and the longest active playoff appearance streak in the four major American professional sports.
The finals concluded on May 25 with the Pittsburgh Penguins winning the Stanley Cup, defeating the Minnesota North Stars in the final series four games to two. Pittsburgh forward Mario Lemieux was awarded the Conn Smythe Trophy as Most Valuable Player of the playoffs.
This was the first NHL playoffs without any series sweeps since the 1972–73 season. In addition, this season set the record for most playoff games played with 92 which stood until 2014.
In the 1990–91 season, teams qualified based on their division standing at the end of the regular season. Playoffs then proceeded among the top four teams in each division, providing a division winner. The two division winners of each conference then played off to provide a conference winner. The two conference winners then played off in the final to produce a Stanley Cup champion.
The following teams qualified for the playoffs:
- Boston Bruins, Adams Division champions, Prince of Wales Conference regular season champions – 100 points
- Montreal Canadiens – 89 points
- Buffalo Sabres – 81 points
- Hartford Whalers – 73 points
- Pittsburgh Penguins, Patrick Division champions – 88 points
- New York Rangers – 85 points
- Washington Capitals – 81 points
- New Jersey Devils – 79 points
- Chicago Blackhawks, Norris Division champions, Clarence Campbell Conference regular season champions, Presidents' Trophy winners – 106 points
- St. Louis Blues – 105 points
- Detroit Red Wings – 76 points
- Minnesota North Stars – 68 points
- Los Angeles Kings, Smythe Division champions – 102 points
- Calgary Flames – 100 points
- Edmonton Oilers – 80 points
- Vancouver Canucks – 65 points
(S3) Edmonton Oilers vs. (N4) Minnesota North Stars
Minnesota's series victory was the first time since realignment in 1981 that the Clarence Campbell Conference was not represented by a Canadian or Smythe Division team in the Stanley Cup Finals.