The WHA expanded by adding the Indianapolis Racers and Phoenix Roadrunners, and splitting into 3 divisions (Western, Eastern, and Canadian). The top two teams in each division qualified for the playoffs along with the two next best teams overall. Prior to the season, Southern California welcomed the Jersey Knights, who moved to San Diego and became the Mariners, and said goodbye to the Los Angeles Sharks, who moved to Detroit and became the Michigan Stags. Midway through the season, the Stags moved to Baltimore and became the Blades; they folded for good after the season. Chicago also folded at season's end. Also, the New England Whalers left Boston for Hartford, but played the first half of the season in Springfield, Massachusetts until construction on the Hartford Civic Center was finished.
The NHL also expanded this season, to 18 teams, making a total of 32 clubs playing major professional hockey in North America. This number has not been surpassed since; the NHL is scheduled to field 32 teams, beginning in 2021.
Eight teams qualified for the playoffs; the top two teams in each division and the next two teams with the highest point totals. The teams were then pooled together, according to point totals, to determine quarter-final match-ups. The three division winners were guaranteed the top three seeds, according to their point totals. Teams were not "reseeded" after the quarter-final round.