The Dirty War (Spanish: Guerra Sucia), also known as the Process of National Reorganization (Spanish: Proceso de Reorganización Nacional or El Proceso), was the name used by the Argentine Military Government for a period of state terrorism in Argentina from roughly 1974 to 1983 (some sources date the beginning to 1969), during which military and security forces and right-wing death squads in the form of the Argentine Anticommunist Alliance (Triple A) hunted down and killed left-wing guerrillas, political dissidents, and anyone believed to be associated with socialism. The victims of the violence were 7,158 left-wing activists, terrorists and militants, including trade unionists, students, journalists and Marxists and Peronist guerrillas and their support network in the Montoneros believed to be 150,000-250,000-strong and 60,000-strong in the ERP, as well as alleged sympathizers. The official number of disappeared is reported to be 13,000. Some 10,000 of the "disappeared" were guerrillas of the Montoneros (MPM) and the Marxist People's Revolutionary Army (ERP). The leftist guerrillas caused at least 6,000 casualties among the military, police forces and civilian population, according to a National Geographic Magazine article in the mid-1980s. The "disappeared" included those thought to be a political or ideological threat to the military junta, even vaguely, and they were killed in an attempt by the junta to silence the opposition and break the determination of the guerrillas. The worst repression occurred after the guerillas were largely defeated in 1977, when the church, labor unions, artists, intellectuals and university students and professors were targeted. The junta justified this mass terror by exaggerating the guerrilla threat, and even staged attacks to be blamed on guerillas and used frozen dead bodies of guerilla fighters that had been kept in storage for this purpose.

Dirty War may refer to:

The Dirty War (Spanish: Guerra Sucia) refers to the Mexican theater of the Cold War, an internal conflict between the Mexican PRI-ruled government and left-wing student and guerrilla groups in the 1960s and 1970s under the presidencies of Luis Echeverría and José López Portillo. The war was characterized by a backlash against the active student movement of the late 1960s which terminated in the Tlatelolco massacre at a 1968 student rally in Mexico City, in which 30 to 300 (official report, non-governmental sources claim thousands) students were killed, and by the Corpus Christi massacre, a massacre of student demonstrators in Mexico City on June 10, 1971. During the war, government forces carried out disappearances, estimated at 1,200, systematic torture, and "probable extralegal executions".

There were several barely connected groups fighting against the government during this period. Among the most important, the September 23 Communist League was at the forefront of the conflict, active in several cities throughout Mexico, drawing heavily from Christian Socialist and Marxist student organizations. They carried out confrontations with Mexican security forces, several kidnappings, and attempted to kidnap Margarita López Portillo, the sister of the president. In Guerrero, the Party of the Poor, ostensibly fighting against landholder impunity and oppressive police practices in rural areas, was led by the ex-teacher Lucio Cabañas; they carried out ambushes of the army and security forces and the abduction of Guerrero's governor-elect.