The 1965–66 NHL season was the 49th season of the National Hockey League. Six teams each played 70 games. The Montreal Canadiens won their second consecutive Stanley Cup as they defeated the Detroit Red Wings four games to two in the final series.
League business 
A new trophy was introduced for this season. Jack Adams won the first Lester Patrick Trophy for his contribution to hockey in the United States.
February saw the momentous announcement that six conditional franchises had been awarded to Los Angeles, San Francisco, St. Louis, Minneapolis-St. Paul, Philadelphia and Pittsburgh, all to begin play in 1967. The St. Louis franchise was surprising, as no formal application from the city had been tendered. It was awarded to fulfill the wishes of James D. Norris and Arthur Wirtz, owners of the Chicago Black Hawks, who also owned the St. Louis Arena, which they wanted to sell.
On the debit side, a strong bid from Vancouver was rejected, much to the anger of many Canadians and the protest of their Prime Minister Lester Pearson. A rumor was widely spread — fuelled by a corroborating statement from Leafs' general manager Punch Imlach that the Toronto and Montreal owners had vetoed the bid out of a dislike for sharing the proceeds from television broadcasts of the games.
Rule changes 
The only significant rule change for this season was a requirement that the teams suit up two goaltenders for each game.
Regular season 
Among notable players to debut during this season were Ed Giacomin for the Rangers, Bill Goldsworthy for the Bruins, Ken Hodge for Chicago and Mike Walton for Toronto. In the meantime, however, the career of future Hockey Hall of Famer Ted Lindsay was over, as his request for reinstatement as an active player was vetoed by the Toronto ownership.
Gordie Howe scored his 600th NHL goal in Montreal on November 27 in a 3–2 loss to the Canadiens to the cheers of the local fans. Among lesser milestones in the season were Frank Mahovlich's 250th goal and Johnny Bucyk's and Claude Provost's 200th.
In an unusual incident, the Red Wings' jerseys were stolen from the visitors' dressing room in Montreal the night before a January game, and Detroit was compelled to play in the uniforms of their junior farm team in Hamilton, which were express shipped to Montreal in time for the match.
James D. Norris, owner of the Chicago Black Hawks, died of a heart attack in late February.
Final standings 
The second game of the semi-final series between Detroit and Chicago on April 10, in which Detroit won by the score of 7–0, was nationally televised in the United States.
For the fourth straight year, it was Montreal vs. Toronto and Detroit vs. Chicago in the first round. The Canadiens were victorious over the Leafs in four straight games, while the Wings beat the Hawks in six.
Playoff bracket 
(1) Montreal Canadiens vs. (3) Toronto Maple Leafs 
(2) Chicago Black Hawks vs. (4) Detroit Red Wings 
Behind the skilled goaltending of Roger Crozier, who had missed parts of the regular season with illness, the Red Wings won the first two games of the Finals. However, Crozier was injured in the fourth game and the Canadiens won the Cup four games to two. Roger Crozier won the Conn Smythe Trophy as the outstanding player of the playoffs.
Bobby Hull set a new record for goals in a season with 54 and a new record for points in a season with 97, earning him the Art Ross Trophy and his second straight Hart Trophy as the league's most valuable player. No left-winger would pace the NHL in points again until Alexander Ovechkin in 2007–08. Jacques Laperrière of Montreal won the Norris Trophy as best defenceman.
All-Star teams 
|Glenn Hall, Chicago Black Hawks
||Gump Worsley, Montreal Canadiens
|Jacques Laperriere, Montreal Canadiens
||Allan Stanley, Toronto Maple Leafs
|Pierre Pilote, Chicago Black Hawks
||Pat Stapleton, Chicago Black Hawks
|Stan Mikita, Chicago Black Hawks
||Jean Beliveau, Montreal Canadiens
|Gordie Howe, Detroit Red Wings
||Bobby Rousseau, Montreal Canadiens
|Bobby Hull, Chicago Black Hawks
||Frank Mahovlich, Toronto Maple Leafs
Player statistics 
Scoring leaders 
Note: GP = Games played, G = Goals, A = Assists, Pts = Points, PIM = Penalties in minutes
Leading goaltenders 
Note: GP = Games played; Min - Minutes Played; GA = Goals Against; GAA = Goals Against Average; W = Wins; L = Losses; T = Ties; SO = Shutouts
The following is a list of players of note who played their first NHL game in 1965–66 (listed with their first team, asterisk(*) marks debut in playoffs):
Last games 
The following is a list of players of note that played their last game in the NHL in 1965–66 (listed with their last team):
See also 
- Diamond, Dan, ed. (1994). Years of glory, 1942-1967: the National Hockey League's official book of the six-team era. Toronto, ON: McClelland and Stewart. ISBN 0-7710-2817-2.
- Diamond, Dan, ed. (2000). Total Hockey. Total Sports. ISBN 1-892129-85-X.
- Dinger, Ralph, ed. (2011). The National Hockey League Official Guide & Record Book 2012. Toronto, ON: Dan Diamond & Associates. ISBN 978-1-894801-22-5.
- Dryden, Steve, ed. (2000). Century of hockey. Toronto, ON: McClelland & Stewart Ltd. ISBN 0-7710-4179-9.
- Duplacey, James (1996). The annotated rules of hockey. New York, NY: Lyons & Burford, Publishers. ISBN 1-55821-466-6.
- Fischler, Stan; Fischler, Shirley; Hughes, Morgan; Romain, Joseph; Duplacey, James (2003). The Hockey Chronicle: Year-by-Year History of the National Hockey League. Lincolnwood, IL: Publications International Inc. ISBN 0-7853-9624-1.
- McFarlane, Brian (1973). The Story of the National Hockey League. New York, NY: Pagurian Press. ISBN 0-684-13424-1.