William Lyon Mackenzie Collegiate Institute is a semestered secondary school located in Toronto, Ontario. It was built in 1960 to accommodate the skyrocketing number of new students in what was then known as North York, and to ease overcrowding at Northview Heights Secondary School. Being located near another high school, Northview Heights Institute of Technology, the school is rumoured to have been called "Southview Heights Institute of Technology", because of the provocative initials. However, it was called Southview Heights Secondary School. Ultimately, William Lyon Mackenzie, the first mayor of Toronto and leader of the Upper Canada Rebellion in 1837, was selected.