The Organisation armée secrète (OAS, "Secret Army Organisation") was a far-right dissident French paramilitary organisation during the Algerian War, founded in 1961 by Raoul Salan, Pierre Lagaillarde and Jean-Jacques Susini. The terrorist movement was particularly active in the final phase of the Algerian War and wanted to prevent Algeria's independence from French colonial rule by all means. The OAS carried out bombings, assassinations, and acts of torture that resulted in over 2,000 deaths. Its motto was L’Algérie est française et le restera ("Algeria is French and so will remain").
The OAS was formed from existing networks, calling themselves "counter-terrorists", "self-defence groups", or "resistance", which had carried out attacks on the Algerian National Liberation Front (FLN) and their perceived supporters since early in the war. It was officially formed in Francoist Spain, in Madrid in January 1961, as a response by some French politicians and French military officers to the 8 January 1961 referendum on self-determination concerning Algeria, which had been organised by President de Gaulle.