Lawrence John Cannon (November 18, 1852 – January 30, 1921) was a Canadian lawyer and judge.

Born in Quebec City, Canada East, the son of Lawrence Ambrose Cannon and Mary Jane Cary, his godfather was Augustin-Norbert Morin. Cannon studied at the Séminaire de Québec and the Séminaire de Nicolet before receiving a law degree from the Université Laval. He was called