The 1978 Maine gubernatorial election took place in the US state on November 7, 1978. Incumbent Independent Governor James B. Longley chose not to run for re-election, holding himself to the one-term pledge he made when he was elected in 1974. Attorney General Joseph E. Brennan of the Democratic Party defeated both challenger Republican Linwood E. Palmer Jr. and right-wing independent candidate Herman Frankland. Richard Carey unsuccessfully ran for the Democratic nomination, while Charles Cragin unsuccessfully ran for the Republican nomination.