Isidore Proulx (March 13, 1840 – July 28, 1904) was an Ontario farmer, merchant and political figure.

He represented Prescott in the House of Commons of Canada, as a Liberal Party member from 1891 to 1904.

Proulx ran unsuccessfully in the riding of Deux-Montagnes for a seat in the Quebec legislative assembly in 1874.

His first election in 1891 was declared invalid after an appeal but he won the subsequent by-election.

After his death in office in 1904, his son Edmond was elected to replace him in the House of Commons.