Georges-Isidore Barthe (November 16, 1834 – August 11, 1900) was a Quebec lawyer, publisher, journalist, and political figure. He represented Richelieu in the Canadian House of Commons as an Independent Conservative from 1870 to 1872 and 1874 to 1878.
He was born Isidore Barthe in Restigouche (now Listuguj Mi'gmaq First Nation), Lower Canada, in 1834 and studied at the Séminaire de Nicolet. He articled in law and was called to the bar in 1856. With a partner, he published a newspaper Le Bas-Canada which advocated an independent Lower Canada; he went on to publish several other newspapers. Barthe was the first secretary-treasurer for Trois-Rivières in 1855 to 1857. In 1861, he married Joséphine-Charlotte, the daughter of Jean-Baptiste Meilleur. He was elected mayor of Sorel in 1864.
Barthe was elected to represent Richelieu in an 1870 by-election after the death of Thomas McCarthy; he was defeated in 1872 but reelected in 1874. In 1882, Barthe returned to Trois-Rivières. From 1887 to 1894, he served as magistrate in the district court of Trois-Rivières. In 1894, he founded L'Indépendance canadienne which advocated a more decentralized Canadian union. In 1897, he was named official translator for the House of Commons.
He died in Ottawa in 1900.
His brother Joseph-Guillaume was also a lawyer and journalist and was a member of the Legislative Assembly of the Province of Canada.