Revolutionary Catalonia (July 21, 1936 – 1939) was the part of Catalonia (a region in northeast Spain) controlled by the anarchist and socialist trade unions, parties, and militias during the Spanish Civil War. These included the Confederación Nacional del Trabajo (CNT, National Confederation of Labor) which was the dominant labor union at the time and the closely associated Federación Anarquista Ibérica (FAI, Iberian Anarchist Federation). The Unión General de Trabajadores (General Worker's Union), the POUM and the Unified Socialist Party of Catalonia (which included the Communist Party of Catalonia) were also involved. Although the Catalonian Generalitat was nominally in power, the trade unions were de facto in command of most of the economy and military forces.
Socialist rule of the region began with the Spanish Revolution of 1936, resulting in workers' control of businesses and factories, collective farming in the countryside, and attacks against Spanish nationalists and the Catholic clergy. The growing influence of the Communist Party of Spain's (PCE) Popular Front government and their desire to nationalize revolutionary committees and militias brought it into conflict with the CNT and POUM, resulting in the May Days and the eventual replacement of the CNT by the PCE as the major political force in Catalonia until the arrival of the fascists.