All municipalities in the Canadian province of Ontario held elections on November 10, 1980, to elect mayors, reeves, councillors, and school trustees. Some areas also held local referendums.
Incumbent mayors were defeated in several cities. The most closely watched contest was in Toronto, where challenger Art Eggleton defeated incumbent mayor John Sewell. In Hamilton, Jack MacDonald was ousted by William Powell. In Brantford, Dave Neumann defeated incumbent mayor Charles Bowen, while in Oshawa, Allan Pilkey defeated incumbent Jim Potticary.
Several other incumbent mayors were reelected, including Marion Dewar in Ottawa, Jim Gordon in Sudbury, Ross Archer in Barrie, Hazel McCallion in Mississauga, Bert Weeks in Windsor and Morley Rosenberg in Kitchener.