Keiller MacKay Collegiate Institute (KMCI, Keiller MacKay) is a medium-sized public high school building located in Toronto's west end close to the intersection of Islington Avenue and Highway 401.

KMCI, Etobicoke’s twentieth and final conventional high school, was constructed in 1970 and opened its doors in September 1971.

The school was named after John Keiller MacKay, who served as the 19th Lieutenant Governor of Ontario from 1957 to 1963.

The school colours were green and blue, and its mascot was a Saber-toothed cat.

[1] The Keiller Mackay Room is currently located in the TDSB's West Education Office, the former headquarters of the EBE.