The 1990–91 NCAA Division III men's ice hockey season began in October 1990 and concluded on March 16 of the following year. This was the 18th season of Division III college ice hockey.
Championship: March 9, 1991 † indicates division regular season champions ~ indicates division tournament champions * indicates conference tournament champion
Championship: March 4, 1991 † indicates conference regular season champion * indicates conference tournament champions ^ Plattsburgh State was ineligible for tournament play in 1991 after being put on probation by the NCAA due to rules violations