The Imperial Oil Building, now known as Imperial Plaza, is a skyscraper located at 111 St. Clair Avenue West in Toronto, Ontario, Canada. The 21-storey building was completed in 1957 as the headquarters of Imperial Oil, Canada's largest oil company. The building's design had previously been rejected for a proposed new Toronto City Hall. After several decades of use as the head office of Imperial Oil, the building was sold in 2010 and converted into a condominium apartment building.