Canadian Forces Base Toronto (also CFB Toronto) is a former Canadian Forces base that operated at the site of Downsview Airport in Toronto, Ontario. The airfield is currently referred to as the 'YZD district' for residential and commercial redevelopment by Northcrest Developments since purchasing property rights of the site on 17 August 2024, following Bombardier's relocation to a new facility at Toronto's Pearson Airport.

The Downsview Lands were part of an extensive land parcel acquired by the British Crown in 1787 from the Mississauga Nation in what is referred to as the Toronto Purchase. "Downsview" received its name in the 1830s after a farm on the property that was called "Downs View", attributed to its commanding vista of Lake Ontario to the south, looking "down" from the plateau. In the 1950s, the area was connected with Toronto to the south when Dufferin Street and the Toronto, Simcoe and Huron Railway were constructed.

In 1929 de Havilland Aircraft of Canada constructed an aircraft manufacturing plant, hangar and airfield in the area then known as Downsview. The airfield was adjacent to the railway (then operated by Canadian National Railway) and affected the grid-like alignment of roads. Following World War II, the Department of National Defence (DND) was in need of property for stationing Royal Canadian Air Force (RCAF) squadrons to protect the concentration of industry and population in southern Ontario. In 1947, the federal government acquired and consolidated 270 properties in Downsview surrounding the De Havilland manufacturing plant, including land on both sides of the railway line. This large tract was developed in the ensuing years as RCAF Station Downsview and became part of the Canadian military's front-line defence of the region.

The 1 February 1968 unification of the RCAF, Royal Canadian Navy and Canadian Army to form the Canadian Forces saw RCAF Station Downsview renamed Canadian Forces Base Toronto (Downsview), later shortened to Canadian Forces Base Toronto (or CFB Toronto). Operational units continued to use CFB Toronto through the 1970s and 1980s.

The first of several non-military events took place in 1984 with the Papal Visit by Pope John Paul II, during which he held an outdoor mass for hundreds of thousands of worshippers.

Declining use of the base led the Government of Canada to close and decommission CFB Toronto. When this was announced in 1994, the government stipulated "the existing DND-owned lands associated with the Downsview site will be held in perpetuity and in trust primarily as a unique urban recreational greenspace for the enjoyment of future generations." The base closed on 1 April 1996, the 72nd anniversary of the Royal Canadian Air Force, along with its Detachment on Avenue Road. In 1995, the "Downsview Framework Plan" was released and the Canada Lands Company was directed to manage the planning and development process for the property.

CFB Toronto is still represented in the area of Denison Armoury, according to the Canadian Armed Forces official website map used to locate CFRC locations.

A series of homes for Canadian Forces personnel were built at the corner of Keele Street and Sheppard Avenue West (William Baker Park) and at the south end of the base property (Stanley Greene Park). Access to the north end housing on Robert Woodhead Crescent and John Drury Drive was restricted to base personnel and fenced off from the neighbouring properties, as was the south end housing on Frederick Tisdale circle.