The flag of Brunei is set on a yellow field and is cut through its centre by a diagonal white stripe and a diagonal black stripe, with the white stripe positioned above the black stripe and being slightly wider in width. At the centre of the flag is the coat of arms of Brunei. A version of this flag without the coat of arms was first used in 1906 before the coat of arms was added to the flag on 29 September 1959.
The flag's main colour of yellow represents the Sultan of Brunei (yellow is a traditional colour of royalty in Asia). The flag's white and black stripes represent the two Chief Ministers of Brunei - the Pengiran Bendahara (First Minister, symbolised by the flag's white stripe) and the Pengiran Pemancha (Second Minister, symbolised by the flag's black stripe).
The flag of Brunei was designed by Yura Halim. The flag's ratio is 1:2.