The Bruins–Canadiens rivalry is a National Hockey League (NHL) rivalry between the Boston Bruins and Montreal Canadiens. It is considered "one of the greatest rivalries in sports." Retired Bruins' forward Bob Sweeney, who played for the Bruins between 1986–87 and 1991–92, once called it among the "top three rivalries in all of sports,... right up there with the... New York Yankees–Boston Red Sox." The two teams have played each other more times, in both regular season play and the Stanley Cup playoffs combined, than any other two teams in NHL history.

Through the conclusion of the 2024–25 season, the two teams have played each other a total of 943 times, with the Canadiens leading the overall series with 471 wins, 355 losses, 103 ties and 12 overtime losses. In the playoffs, the two teams have met in 34 series for a total of 177 games, the most in NHL history. Both teams also have faced each other nine times in game sevens, more than any other pair of opponents in NHL history.

Origins The first-ever professional ice hockey team in the United States to play in the National Hockey League, the Boston Bruins, started play on Monday, December 1, 1924, as one of two NHL "expansion teams" in its 1924–25 season, along with the Montreal Maroons – these two teams faced each other in the Bruins' inaugural NHL regular season game at their Boston Arena indoor hockey rink that night, with the Bruins winning by a 2–1 score on home ice, with a Canadian skater for the Bruins, Smokey Harris scoring the first-ever Bruins goal. However, only one week later, on December 8, the other Montreal hockey team, the veteran Canadiens were the opponents for the hometown Bruins, with the Canadiens coming from behind to defeat Boston in a 4–3 win.

For their first fourteen seasons, Boston did not have a particularly notable rivalry with either Montreal team – the Canadiens' owner had actually worked behind the scenes to admit the Maroons in the expectation they would be his team's most lucrative rival. After their second season, three more U.S. teams were added and the Bruins were placed in the newly formed American Division while the Canadiens entered the Canadian Division. The Boston-Montreal rivalry only truly began after the owners of the financially troubled Maroons, who had subsequently acquired the Canadiens, decided to contract their original franchise. The Maroons' 1938 demise left the Canadiens without a crosstown rival and left the league with only seven teams, thus compelling it to realign into a single division.

Boston and Montreal have been in the same division for the vast majority of seasons since that time. The first exception came in the 1970s when the Bruins were placed in the Adams Division and the Canadiens in the Norris Division, however the distinction was largely academic since during this time the league played used a balanced schedule and league-wide playoff format – when the league revamped its scheduling format and playoff format to better account for geography, conferences and divisions in 1981 the Canadiens were realigned to the Bruins' Adams Division. The 2020–21 season, in which the COVID-19 pandemic forced a temporary division realignment to avoid cross-border travel, caused Montreal to be placed in an all-Canadian "North" division and Boston in an Atlantic-Metro hybrid "East" division, and resulted in the first season of play in which the Canadiens and Bruins did not face each other.

Although the Canadiens–Toronto Maple Leafs rivalry is actually the oldest in the league dating back to the NHL's founding in 1917, the Toronto Maple Leafs were placed in the opposite conference between 1981 and 1998, limiting the number of Montreal–Toronto games per season during those years compared to that of Boston–Montreal.

Post-War through the 1950s: Canadiens dominance On April 8, 1952, Maurice "Rocket" Richard scored one of the most famous goals of all time, described variously as "the greatest in the history of the game" and "most beautiful in the history of the world." As blood dripped down his face after an earlier injury that gave him a concussion, he scored the series-winning goal of the 1952 Stanley Cup semifinals. Richard had left the game but returned to the bench in the third period, wearing a bandage. Richard, although somewhat dazed, jumped off the bench and drove to the net to score past a surprised Sugar Jim Henry, the Boston Bruins' goaltender. After the goal, showing tremendous respect and sportsmanship, a photograph was taken of Henry shaking hands with the bandaged Richard. It is considered to be one of the most famous images ever to be captured in sports.

1955: Violence leads to Richard Riot

On March 13, 1955, an on-ice episode sparked one of the worst incidents of hockey-related violence in history. Maurice Richard was part of a violent confrontation in a game against the Bruins. Bruins defenceman Hal Laycoe, who had previously played for the Canadiens, high-sticked Richard in the head during a Montreal power play. Richard required five stitches to close a cut that resulted from the high-stick. Referee Frank Udvari signaled a delayed penalty, but allowed play to continue because the Canadiens had possession of the puck. When the play ended, Richard skated up to Laycoe, who had dropped his stick and gloves in anticipation of a fight, and struck him in the face and shoulders with his stick. The linesmen attempted to restrain Richard, who repeatedly broke away from them to continue his attack on Laycoe, eventually breaking a stick over his opponent's body before linesman Cliff Thompson corralled him. Richard broke loose again and punched Thompson twice in the face, knocking him unconscious. Richard then left the ice with the Canadiens' trainer. According to Montreal Herald writer Vince Lunny, Richard's face looked like a "smashed tomato." Richard was given a match penalty and an automatic $100 fine, while Laycoe received a five-minute major penalty and a ten-minute misconduct, which called for an automatic $25 fine, for the high stick.

Boston Police attempted to arrest Richard in the dressing room after the game ended, but were turned back by Canadiens players who barred the door, preventing any arrest. Richard was never arrested for the incident, as Bruins management finally persuaded the officers to leave with a promise that the NHL would handle the issue. He was instead sent to the hospital by team doctors after complaining of headaches and stomach pains.

It was Richard's second incident with an official that season. He had slapped a linesman in the face in Toronto the previous December and was fined $250. Upon hearing the referee's report, NHL President Clarence Campbell ordered all parties to appear at a March 16 hearing at his office in Montreal.

The March 16 hearing was attended by the on-ice officials, Richard, Laycoe, Montreal assistant general manager Ken Reardon, Boston general manager Lynn Patrick, Montreal head coach Dick Irvin and NHL referee-in-chief Carl Voss. In his defence, Richard contended that he was dazed and thought Thompson was one of Boston's players. He did not deny punching or attacking Laycoe. After the hearing, Campbell issued a 1,200-word statement to the press and said that "Richard will be suspended from all games both league and playoff for the balance of the current season." The suspension—the longest for an on-ice incident ever issued by Campbell in his 31 years as League president—was considered by many in Montreal to be unjust and severe. No sooner had the judgment been handed out than the NHL office (then located in Montreal) was deluged with hundreds of calls from enraged fans, many of whom made death threats to Campbell.

Campbell stood firm, however, and moreover announced that he would be attending the Canadiens' next home game against the Detroit Red Wings on March 17. Midway into the first period, Campbell arrived with his fiancée. Outraged Canadiens fans immediately began pelting them with eggs, vegetables and various debris, with more being thrown at him each time the Red Wings scored, building up a 4–1 lead on Montreal. The continuous pelting of various objects stopped when a tear gas bomb was set off inside the Forum not far from where Campbell was sitting. The Forum was ordered evacuated and Campbell ruled the game forfeited to the Red Wings.

That was the last straw for Canadiens fans, as a riot ensued outside the Forum, causing $500,000 in damage to the neighbourhood and the Forum itself. Hundreds of stores were looted and vandalized within a 15-block radius of the Forum. Twelve policemen and 25 civilians were injured. The riot continued well into the night, with police arresting people by the truckload. Local radio stations, which carried live coverage of the riot for over seven hours, had to be forced off the air. The riot was eventually over at 3 a.m., leaving Montreal's Rue Ste-Catherine in shambles.

The suspension came when Richard was leading the NHL in scoring and the Canadiens were battling the Detroit Red Wings for first place. Richard's suspension cost him the 1954–55 scoring title, the closest he ever came to winning it, and the Canadiens first place; on the final day of the season, the Canadiens lost to the Red Wings, 6–0. When Richard's teammate Bernie Geoffrion surpassed Richard in scoring on the last day of the regular season, the Canadiens' fans booed him.

Laycoe was booed by Canadiens' fans when the two teams met again in the Stanley Cup semifinals a few days afterward. A teammate, Ed Sandford recalled, "I drew Laycoe as my taxi teammate. When we got to the Forum, the police were waiting for us, and they escorted us into the building and to the dressing room past a bunch of angry fans. Then every time Laycoe came on the ice, the crowd booed him."

1960s and 1970s The Bruins and Canadiens made up 16 of the possible 30 Stanley Cup Final appearances between and . The Bruins went 2–3 and Canadiens went 10–1 in Final appearances. The two teams went head-to-head in the and 1978 Stanley Cup Final. The only Final that neither team appeared during this period was in , which was a showdown between the Philadelphia Flyers and Buffalo Sabres. During this period, the Bruins and Canadiens reigned exclusively as Stanley Cup champions, except in 1967 when it was won by the Toronto Maple Leafs and the Philadelphia Flyers in and 1975.

1965 to early 1970s: Dominance by Montreal over resurgent Boston Both teams won Stanley Cups between – against the St. Louis Blues, who entered play as an expansion team in the 1967–68 season, all series against the Blues were four-game sweeps. The Canadiens beat the Blues in 1968 and . The 1969 east semifinals was described by Sports Illustrated as "the most intriguing Stanley Cup hockey series in a decade" as the upcoming Stanley Cup Final against St. Louis would be considered a "formality." It pitted the defending champions Canadiens against the Bruins, an ascendent team since their 1967 trade with Chicago, with superstar defenceman Bobby Orr and regular season scoring champion Phil Esposito (who broke the century mark with 126 points). The Bruins had thought that they had outplayed their opponents in the series, however, it was the Habs who seemed to be in "the right place at the right time", as Jean Beliveau scored the winning goal in the second overtime period at Boston Garden to eliminate the Bruins in six games. In the 1969–70 season, the Canadiens narrowly missed the playoffs on the last day of the regular season, while the Bruins won their first Stanley Cup since on the famous overtime goal by Bobby Orr.