The National Hockey League (NHL) conference finals are the Eastern Conference and Western Conference championship series of the NHL. The conference finals are each a best-of-seven series, and comprise the third round of the Stanley Cup playoffs. The two series are played in mid-to-late May (early June in 1995 and 2013, due to labour disputes that delayed the start of the season and September in 2020 due to the COVID-19 pandemic). The winners of the Eastern and Western Conference finals receive the Prince of Wales Trophy and Clarence S. Campbell Bowl, respectively, and advance to face each other in the Stanley Cup Finals.

Before the 1967–68 season, the NHL was made up only of a single division. From the 1967–68 season through the 1973–74 season, the NHL was made up of two divisions (as opposed to conferences), the East Division and the West Division.

Following the 1973–74 season, the NHL again realigned. The East and West Divisions were renamed the Prince of Wales and Clarence Campbell Conferences, respectively. At the time, the new conferences and divisions had little to do with North American geography and geographical references were removed. Furthermore, all playoff teams were seeded regardless of conference.

Beginning in the 1981–82 season, the conferences and the playoffs were realigned. The NHL was hoping to reduce travel costs in the face of a struggling economy and high energy prices. The regular season and playoffs were also altered to emphasize divisional match-ups. Thus, the first official conference finals were held in 1982.

Beginning in the 1993–94 season, the names of conferences and divisions were changed to reflect their geographic locations. At the instigation of then-new NHL commissioner Gary Bettman, the NHL made the change to help non-hockey fans better understand the game, as the National Basketball Association uses geographic-based names for their conferences and divisions, and the National Football League, and Major League Baseball use geographic-based names for their divisions. Therefore, the Campbell Conference became the Western Conference and the Wales Conference became the Eastern Conference. The winner of the Eastern Conference finals still receives the Prince of Wales Trophy, while the winner of the Western Conference finals still receives the Clarence S. Campbell Bowl. The only exception to this practice was the pandemic-affected 2020–21 season that was played without conferences. The league decided in June 2021 to award the trophies (one per team) to the two victors of the Stanley Cup semifinals. After that season, the league revived the conferences for the 2021–22 season.

The Hartford Whalers never advanced to a conference final; however, after they relocated to become the Carolina Hurricanes, they did so six times (2002 as the eventual Cup finalists, 2006 as the eventual Cup champions, 2009, 2019, 2023, and 2025). The original Winnipeg Jets never appeared in the conference finals, and after moving to become the Phoenix Coyotes, the franchise did not even win a playoff series until the 2012 Stanley Cup playoffs when they advanced to the conference finals. Of the 32 teams in the NHL, only the Columbus Blue Jackets, Seattle Kraken, and Utah Mammoth have never appeared in the conference finals.

Another tradition (or rather superstition) that is prevalent among today's NHL players is that no player should touch the Cup itself until his team has rightfully won the Cup. Adding to this superstition is some players' choice to neither touch nor hoist the conference trophies (Clarence S. Campbell Bowl and Prince of Wales Trophy) when these series have been won; the players feel that the Stanley Cup is the true championship trophy, and only it should be hoisted.

However, in 1994, Stephane Matteau, then of the New York Rangers, admitted that he tapped the Wales Trophy with his stick's blade before the overtime period in Game 7 of the Eastern Conference finals. Matteau subsequently scored the game-winning goal in double overtime against the New Jersey Devils. Following the game, Mark Messier, the captain of the Rangers, picked up and raised the Wales Trophy after it was awarded to the team. After winning the Western Conference, Vancouver Canucks captain Trevor Linden lifted the Campbell Bowl. The Rangers prevailed over the Canucks in a seven-game series to win the Cup.