The Art Gallery of Toronto was originally housed in the Grange, a historical house still connected to the gallery. In 1918 it moved into new galleries on its current site, with expansions in 1926 and in 1935. The building had further expansions in 1977 that almost completely obliterated the earlier buildings, and again in the early 1990's when a new front was added to the building. Finally, the 1990's addition was almost completely removed in 2007-2008 when Transformation AGO occurred, a Frank Gehry-designed addition to the building.
Parkin Associates was given a Canadian Architect Award in 1975 for renovations and additions to this building, and Barton Myers and KPMB were given a Canadian Architect Award of Excellence in 1988 for renovations and additions. In 2009, the building was given an Honourable Mention in the Toronto Urban Design Awards in the category Building in Context - Public.