The following is a list of prominent Upper Canada College (UCC) alumni. UCC's alumni are usually known simply as Old Boys (as is common with most all-male private schools). They include:
Jennings, William Tyndale – civil engineer, city engineer for Toronto, and president of the Canadian Society of Civil Engineers (later the Engineering Institute of Canada)[4]
Barrett, Anthony (1964) – founder of Pollution Probe; Chief Financial Officer of the World Wildlife Fund of Canada[1]
Barton, Eric CM (1957) – founder of a leprosy treatment centre in India; principal of UCC[1]
Douglas, Ian CMCDQC – founding president of the Canadian Epilepsy Association; chairman of the National Board of Governors of the Canadian Corps of Commissionaires
Burgess, Thomas Joseph Workman FRSC (1866) – leader in psychiatry in Canada; President of the Société Médico-Psychologique de Québec and American Medico-Psychological Association (later the American Psychiatric Association)[33]