The International Workers' Association (IWA) (Spanish: AIT - Asociación Internacional de los Trabajadores, and in German: IAA-Internationale ArbeiterInnen Assoziation) is an international anarcho-syndicalist federation of various labour unions from different countries. It was founded as the International Workingmen's Association in 1922, at a Berlin congress of anarcho-syndicalist labor unions.
Previously, the same name was used to refer to the unitarian socialistinternational organisation founded in 1864. But this first International wasn't able to withstand the differences between anarchist and Marxist currents, being dissolved some time later. Not only modern IWA-AIT but also the Socialist International and the Communist International find in this first experiment of worldwide working class movement their own origins.