Gustave Geffroy (1 June 1855 – 4 April 1926) was a French journalist, art critic, historian, and novelist. He was one of the ten founding members of the literary organization Académie Goncourt in 1900.
Geffroy is noted as one of the earliest historians of the Impressionist art movement. He knew and championed Monet, whom he met in 1886 in Belle-Île-en-Mer while travelling for research on prisons of the Second Empire. Monet introduced him to Cézanne, who painted his portrait in 1895.
He contributed to the newspaper La Justice from 15 January 1880, and came to know its founder, Georges Clemenceau, who in 1908 appointed him director of the Gobelins tapestry factory, a position he held until his death.
Geffroy was born and died in Paris, and is interred at the Cimetière de Montrouge. A street in Paris's 13th arrondissement, close to the Gobelins Manufactory, bears his name.