John Gabriel Hearn (March 26, 1863 – January 28, 1927) was a businessman and political figure in Quebec.
He represented Québec-Ouest in the Legislative Assembly of Quebec from 1900 to 1904 as a Liberal member.
He studied at the Royal Military College in Kingston from 9 September 1880 until 1884, cadet number 106.
Hearn became a real estate agent and also administered the property accumulated by his father.
He served on the Quebec municipal council and was president of the finance committee from 1896 to 1898.