Isidore Thibaudeau (September 30, 1819 – August 18, 1893) was a Quebec businessman and political figure.

He was born Pierre-Isidore Thibaudeau in Pointe-aux-Trembles, Lower Canada in 1819; his father was a merchant of Acadian origin.

He worked as a clerk in the Quebec City branch of a firm based in Montreal.

Thibaudeau served as a member of the Legislative Council of Quebec from 1867 to 1874, when he was elected to the federal parliament.

His daughter Laura married Esdras Alfred de St-Georges, who served in the Canadian House of Commons.