The NHL’s longest unbeaten streak by a team was 35 games, set by Philadelphia in 1979–80.
The Philadelphia Flyers opened the 1979–80 season with a 35-game unbeaten run, going 25–0–10 before losing to the Minnesota North Stars on January 7, 1980. The streak included both wins and ties, so “unbeaten” is more precise than “winning streak.” Philadelphia’s run remains an NHL record for consecutive games without a loss.
The Flyers finished that regular season with 48 wins, 12 losses, and 20 ties, earning 116 points. They advanced to the Stanley Cup Final, where the New York Islanders defeated them in six games. The record is sometimes mistakenly described as 35 consecutive wins; Philadelphia did not win every game, because ten contests ended in ties under the rules then in use.