An authoritarian military dictatorship ruled Chile for seventeen years, between 11 September 1973 and 11 March 1990. The dictatorship was established after the democratically elected socialist government of Salvador Allende was overthrown in a coup d'état backed by the United States on 11 September 1973. During this time, the country was ruled by a military junta headed by General Augusto Pinochet. The military used the breakdown of democracy and the economic crisis that took place during Allende's presidency to justify its seizure of power. The dictatorship presented its mission as a "national reconstruction". The coup was the result of multiple forces, including pressure from conservative groups, certain political parties, union strikes and other domestic unrest, as well as international factors.

A military dictatorship, or a military regime, is a type of dictatorship in which power is held by one or more military officers. Military dictatorships are led by either a single military dictator, known as a strongman, or by a council of military officers known as a military junta. They are most often formed by military coups or by the empowerment of the military through a popular uprising in times of domestic unrest or instability. The military nominally seeks power to restore order or fight corruption, but the personal motivations of military officers will vary.