Pierre-François Casgrain, PC (August 4, 1886 – August 2, 1950) was a Canadian lawyer and politician. He was Speaker of the Canadian House of Commons from 1936 to 1940. Born in Montreal, Quebec, his father was a physician. Following the death of his mother when he was three years old, he was raised by his grandmother. Casgrain graduated in law from Université Laval and practiced in Montreal where he worked as an organizer for the Liberal Party of Canada and the Quebec Liberal Party. After his death in 1950, he was entombed at the Notre Dame des Neiges Cemetery in Montreal.