Augusto José Ramón Pinochet Ugarte was a Chilean army officer and military dictator who ruled Chile from 1973 to 1990. He was the leader of the military junta from 1973 to 1981, and was declared President of the Republic by the junta in 1974 and thus became the dictator of Chile, and from 1981 to 1990 as de jure president after a new constitution which confirmed him in the office was approved by a referendum in 1980. His time in office remains the longest of any Chilean ruler.

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.