The Ministry of Defence is headquartered within Bolkiah Garrison in Bandar Seri Begawan, the capital of Brunei Darussalam, in the Brunei-Muara District, with the postcode BB3510.

In late 1986, the Ministry of Defence was restructured and reorganised; it currently manages the Royal Brunei Armed Forces, the Royal Brunei Malay Reserve Unit, and also the Gurkha Reserve Unit.

The ministry is sub-divided into two divisions; Civilian Staff (headed by a Permanent Secretary), and Military Staff (headed by Commander of Royal Brunei Armed Forces).

[5][7][10] The Second Minister of Defence (Menteri Pertahanan Kedua) portfolio was established in 2018 as a result of a cabinet reshuffle, and was held by Halbi Mohd Yussof.

[6][11][a] The Deputy Minister of Defence (Timbalan Menteri Pertahanan) portfolio first appeared in the cabinet assembly in 1986.