The 1986 Stanley Cup playoffs, the playoff tournament of the National Hockey League (NHL) began on April 9, after the conclusion of the 1985–86 NHL season. The playoffs concluded on May 24 with the champion Montreal Canadiens defeating the Calgary Flames 4–1 to win the Stanley Cup, in five games.

The Stanley Cup playoffs is the annual elimination tournament to determine the winner of the Stanley Cup, and by default the league champion of the National Hockey League (NHL). The four-round, best-of-seven tournament is held after the NHL's regular season. Eight teams from each of the league's two conferences qualify for the playoffs based on regular season points totals. The final round is commonly known as the Stanley Cup Finals, which matches the two conference champions.