The 1990 Stanley Cup playoffs for the National Hockey League (NHL) championship began on April 5, 1990, following the 1989–90 regular season. The sixteen teams that qualified, from the top four teams of the four divisions, played best-of-seven series. The Conference Champions played a best-of-seven series for the Stanley Cup.

The Conn Smythe Trophy is awarded annually to the most valuable player (MVP) of his team during the National Hockey League's (NHL) Stanley Cup playoffs. It is named after Conn Smythe, the longtime owner, general manager, and head coach of the Toronto Maple Leafs. The Conn Smythe Trophy has been awarded 54 times to 47 players since the 1964–65 NHL season. Each year, at the conclusion of the final game of the Stanley Cup Finals, members of the Professional Hockey Writers' Association vote to elect the player deserving of the trophy. The trophy is handed out by the NHL Commissioner before the presentation of the Stanley Cup and only the winner is announced, in contrast to most of the other NHL awards which name three finalists and are presented at a ceremony. Vote tallies for the Conn Smythe Trophy were released starting in 2017.