The party served as Official Opposition in the Legislative Assembly of Alberta from 1986 to 1993. It was shut out of the legislature following the 1993 election, returning in the 1997 election with two seats. The party won no more than four seats in subsequent elections until the 2015 election, in which it won 54 of the 87 seats in the legislature and formed a majority government. Until 2015, Alberta had been the only province in western Canada — the party's birthplace — where the NDP had never governed at the provincial level. The Alberta NDP was defeated after a single term in the 2019 election by the United Conservative Party–the first time that a governing party in Alberta had been unseated after a single term.