The Ministry of National Defense (Spanish: Ministerio de Defensa Nacional) is the cabinet-level administrative office in charge of "maintaining the independence and sovereignty" of Chile.

It is also charged with planning, directing, coordinating, executing, controlling and informing the defense policies formulated by the President of Chile.

The office officially first came to be on 17 March 1814, when then Supreme Director Francisco de la Lastra dictated the Constitutional Norms approved on that date.

It was abolished the same year by the Spanish authorities when, after the Battle of Rancagua, they re-asserted royal power.

According to Decree 200 of 15 April 1976, the oversight was again expanded to include the National Police (Carabineros and Investigaciones).