The 1917–18 PCHA season was the seventh season of the professional men's ice hockey Pacific Coast Hockey Association league. Season play ran from December 28, 1917, until March 8, 1918. The season was reduced to 18 games per team. The Seattle Metropolitans club would be regular-season PCHA champions, but lost the play-off to the Vancouver Millionaires. The Millionaires then played in the Stanley Cup finals series against Toronto, the NHL champions. Toronto won the best-of-five series 3-2 to win the Cup.
The Spokane franchise folded and the league operated with three teams again. The players were distributed to the other teams.
The league decided to split the schedule with each half's winners playing for the championship. This was revised so that the first and second teams played off for the championship. Previously, playoffs were only held when teams tied for first place. Devised by Frank Patrick as a "second-chance" to increase interest in the league, the idea eventually spread to all North American professional sports.