The National Defence Institute was created on July 12, 1976 by Decree- Law 550-D/76, and successively reorganized, currently governed by Regulatory Decree No. 7/2015 of 31/7/2015.
This Institute was the first in the country to devote itself to the study, research and dissemination of the problems of National Defence. Its predecessor was the Institute of Higher Studies of National Defence (IAEDN), founded in December 1967, whose first director was General Luís Maria Câmara Pina.
Initially, between its foundation and the spring of 1974, the Institute offered two three-month courses in 1972 and 1973, aimed at senior military and civil service officials, with the aim of promoting a better understanding of the national reality and facilitating the interconnection between senior State officials. The building where the National Defence Institute is located in Lisbon, inaugurated in 1973, dates from this period.
After the 25th of April, the institute started to host the Centre of Military Sociology, a situation that continued until 1976. At this stage, Auditorium 1 of the National Defence Institute, now called Auditório Câmara Pina, was used for the major assemblies of the Armed Forces Movement (MFA). The return to the Institute's original mission took place when the Constitution was approved in 1976, when it was re-founded with the designation it still holds today as the National Defence Institute.
Since 1982, IDN has been part of the Ministry of National Defence, with scientific, pedagogical and administrative autonomy. In 1987 the Porto delegation was created, which would later settle in the "Castelo da Foz" (Fort of São João Baptista da Foz), facilities where it currently operates.
In 1996 the first civil director was appointed, Nuno Severiano Teixeira and in 2019 the first female director, Helena Carreiras.