Postal codes in Brunei Darussalam are known as postcodes (Malay: poskod), and they are alphanumeric; consisting of two letters followed by four digits. Postcodes in Brunei are issued by the Postal Services Department, a government department under the Ministry of Communications.

A Bruneian postcode has six characters, consisting of two uppercase letters and immediately followed by four digits (numbers). Examples of postcodes are BB3713, which represents the postcode area Anggerek Desa; KB4533 which represents Panaga; and BA2110 which represents Jabatan Hal Ehwal Masjid, or the Department of Mosque Affairs.

The components of a postcode comprises four types of codes. They are specifically represented by their district (Malay: daerah), then it mukim (sub-district), and then villages and post offices.

The first of the two postcode letters of the denotes the district, which corresponds to the name of the specific districts of Brunei.

The second letter denotes the mukim code, corresponding directly to the mukims or sub-districts of Brunei, the country's second-level administrative divisions.

Following the two letters, the first two number digits represent the village code. Usually, it corresponds directly to the villages (Malay: kampung), the country's third- and lowest-level administrative divisions. However, some larger villages may have more than one postcode area. Some postcode areas may also represent defunct villages, or villages which have been subsumed under other nearby villages.

The last two digits represent the post office code, which generally correspond to the post office of, or nearest to, the village or mukim. A few may also correspond to the function of the place, and this exclusively refers to government ministries or departments. They have postcodes with the last digit '0'. One example is BA2110, which represents the Department of Mosque Affairs, a government department under the Ministry of Religious Affairs.

A complete postcode represents either an area or a government agency.