The Princess Margaret Cancer Centre (previously, Princess Margaret Hospital) is a scientific research centre and a teaching hospital in Toronto, Ontario, Canada, affiliated with the University of Toronto Faculty of Medicine as part of the University Health Network.

[3] The hospital is situated near the intersection of University Avenue and College Street within the Discovery District of downtown Toronto, an area with high concentration of biomedical research institutions.

Its related research arm, the Ontario Cancer Institute (OCI), works in conjunction with the hospital in a mutually beneficial relationship.

The Princess Margaret's research program ranked fourth in terms of the percentage of publications cited in high-impact oncology journals.

Designed by the architect Henry Sproatt, it was originally located at 500 Sherbourne Street (now a condo complex) near the former Wellesley Hospital.