Movimiento de Agrupaciones Obreras ('Workers Groups Movement', abbreviated MAO) was a political labour organization in Argentina. MAO was founded in mid-1957 by a Nahuel Moreno's Trotskyist tendency (which had been organized in the Revolutionary Workers Party, POR, until that party had merged into the Socialist Party of the National Revolution in 1954). MAO formed part of the trade unionist resistance to the "Revolución Libertadora".