The 1911–12 NHA season was the third season of the National Hockey Association (NHA). Four teams played 18 games each. The Quebec Bulldogs would win the league championship and take over the Stanley Cup.
Two NHA franchises would be dormant this season. Because the O'Briens had decided to give up hockey, the Renfrew Creamery Kings were disbanded prior to the season, with the players distributed to the other teams by a draw of names. Two new teams based in Toronto intended to operate this season, the 'Torontos' and the 'Tecumsehs', but the new Arena Gardens would not be ready for play this season, so neither team played. This left four teams to play 18 games each.
The rule changes implemented for this season introduced the format of play seen today.
For this season, the number of players per side was reduced to six by the elimination of the rover position. This was opposed by several teams, including the champion Ottawa team whose 'puck possession' style of play was dependent on the rover. The team would attempt during this season and next to get the league to return to seven-man hockey.