The University of Toronto (U of T) is a public research university whose main campus is located on the grounds that surround Queen's Park in Toronto, Ontario, Canada. It was founded by royal charter in 1827 as King's College, the first institution of higher learning in Upper Canada. Originally controlled by the Church of England, the university assumed its present name in 1850 upon becoming a secular institution. It has three campuses: St. George, Mississauga, and Scarborough. Its main downtown Toronto campus, St. George, is the oldest of the three and operates as a collegiate university, comprising 11 colleges, each with substantial autonomy on financial and institutional affairs and significant differences in character and history.

The University of Toronto is the largest university in Canada with a total of 102,431 students across its three campuses. It offers over 700 undergraduate and 200 graduate programs. The university receives the most annual scientific research funding and endowment of any Canadian university. It is also one of two members of the Association of American Universities outside the United States, alongside McGill University in Montreal. Academically, the University of Toronto is noted for influential movements and curricula in literary criticism and communication theory, known collectively as the Toronto School.

The university was the birthplace of insulin, stem cell research, the first artificial cardiac pacemaker, and the site of the first successful lung transplant and nerve transplant. The university was also home to the first electron microscope, the development of deep learning, neural network, multi-touch technology, the identification of the first black hole Cygnus X-1, and the development of the theory of NP-completeness. The University of Toronto is the recipient of both the single largest philanthropic gift in Canadian history, a $250 million donation from James and Louise Temerty in 2020, and the largest ever research grant in Canada, a $200 million grant from the Government of Canada in 2023.

The Varsity Blues are the athletic teams that represent the university in intercollegiate league matches, primarily within U Sports, with ties to gridiron football, rowing and ice hockey. The earliest recorded instance of gridiron football occurred at University of Toronto's University College in November 1861. The university's Hart House is an early example of the North American student centre, simultaneously serving cultural, intellectual, and recreational interests within its large Gothic-revival complex.

As of 2024, 13 Nobel laureates, 6 Turing Award winners, 100 Rhodes Scholars, and 1 Fields Medalist have been affiliated with the university. University of Toronto alumni additionally include five prime ministers of Canada (including William Lyon Mackenzie King and Lester B. Pearson), three governors general of Canada, nine foreign leaders, seventeen justices of the Supreme Court of Canada, and eight mayors of Toronto.