The national flag of Brunei has the crest of Brunei in the centre, on a yellow field. The field is cut by black and white diagonal stripes, although they are officially called parallelograms.

The yellow field represents the Sultan of Brunei. (In Southeast Asia, yellow is traditionally the colour of royalty, and the royal standards of Malaysia and Thailand, along with the presidential flag of Indonesia, also use a yellow field.)

The crest consists of a crescent (symbolizing Islam) joined with a parasol (symbolizing monarchy), and two upturned hands on both sides (signifying the benevolence of the government). Below the crescent is a ribbon. On the crescent and ribbon are Arabic inscriptions translating as "State of Brunei, Abode of peace" and Brunei's motto, "Always in service with God's guidance"

The black and white parallelograms represent Brunei's chief ministers.

The flag in its present form, except for the crest, has been in use since 1906 when Brunei became a British protectorate, following the signing of an agreement between Brunei and Great Britain.

Brunei ⁱ/bruːˈnaɪ/, officially the Nation of Brunei, the Abode of Peace (Malay: Negara Brunei Darussalam, Jawi: نڬارا بروني دارالسلام), is a sovereign state located on the north coast of the island of Borneo, in Southeast Asia. Apart from its coastline with the South China Sea, it is completely surrounded by the state of Sarawak, Malaysia, and it is separated into two parts by the Sarawak district of Limbang. It is the only sovereign state completely on the island of Borneo, with the remainder of the island belonging to Malaysia and Indonesia. Brunei's population was 401,890 in July 2011.

The official national history claims that Brunei can trace its beginnings to the 7th century, when it was a subject state of the Srivijayan empire under the name P'o-li. It later became a vassal state of Majapahit empire before converting to Islam in the 15th century. At the peak of its empire, the sultanate had control that extended over the coastal regions of modern-day Sarawak and Sabah, the Sulu archipelago, and the islands off the northwest tip of Borneo. The thalassocracy was visited by Ferdinand Magellan in 1521 and fought the Castille War in 1578 against Spain. Its empire began to decline with the forced ceding of Sarawak to James Brooke and the ceding of Sabah to the British North Borneo Chartered Company. After the loss of Limbang, Brunei finally became a British protectorate in 1888, receiving a resident in 1906. In the years after the Japanese wartime occupation during World War II, it formalised a constitution and fought an armed rebellion. Brunei regained its independence from the United Kingdom on 1 January 1984. Economic growth during the 1970s and 1990s, averaging 56% from 1999 to 2008, has transformed Brunei Darussalam into a newly industrialised country.