Allan Gordon Sinclair, OC, FRGS (June 3, 1900 – May 17, 1984) was a Canadian journalist, writer and commentator.
Sinclair was born in the Cabbagetown neighbourhood of Toronto, Ontario. In 1916, before finishing his first year of high school, Sinclair dropped out to take a job with the Bank of Nova Scotia. After a few months, he was fired and started working in the administrative office of Eaton's. During World War I, Sinclair served as a part-time soldier in a militia unit of the 48th Highlanders of Canada. After being fired from Eaton's, Sinclair took a junior bookkeeping job with Gutta Percha and Rubber Manufacturing Company, starting in April 1920. It was there that he met co-worker Gladys Prewett. After an off-and-on relationship, the two were married on May 8, 1926.