The cancelled expressways in Toronto were a planned series of expressways in Toronto, Ontario, Canada that were only partially built or cancelled due to public opposition. The system of expressways was intended to spur or handle growth in the suburbs of Toronto, but were opposed by citizens within the city of Toronto proper, citing the demolition of homes and park lands, air pollution, noise and the high cost of construction. The Spadina Expressway, planned since the 1940s, was cancelled in 1971 after being only partially constructed. After the Spadina cancellation, other expressway plans, intended to create a 'ring' around the central core, were abandoned.

King's Highway 427, also known as Highway 427 and colloquially as the 427, is a 400-series highway in the Canadian province of Ontario that runs from the Queen Elizabeth Way (QEW) and Gardiner Expressway in Toronto to Major Mackenzie Drive in Vaughan. It is Ontario's second busiest freeway by volume and the third busiest in North America, behind Highway 401 and Interstate 405 in California. Like Highway 401, a portion of the route is divided into a collector-express system with twelve to fourteen continuous lanes. Notable about Highway 427 are its several multi-level interchanges; the junctions with the QEW/Gardiner Expressway and Highway 401 are two of the largest interchanges in Ontario and were constructed between 1967 and 1971, while the interchanges with Highway 409 and Highway 407 were completed in 1992 and 1995, respectively.