The Brunei River is a river which flows through Brunei and empties into the Brunei Bay towards the north-east direction. The Istana Nurul Iman, the official residence of the Sultan of Brunei, stands on its banks. The Brunei River is the shortest major river in Brunei. It is the major river basin within the Brunei-Muara District, the smallest but most populous district. It flows through the country's capital Bandar Seri Begawan. It is home to Kampong Ayer, the Brunei's traditional village on stilts above the river water.

Brunei, officially State of Brunei, and formally Brunei Darussalam, is a country in Southeast Asia, situated on the northern coast of the island of Borneo. Apart from its coastline on the South China Sea, it is completely surrounded by the Malaysian state of Sarawak, with its territory bifurcated by the Sarawak district of Limbang. Brunei is the only sovereign state entirely on Borneo; the remainder of the island is divided between its multi-landmass neighbours of Malaysia and Indonesia. As of 2023, the country had a population of 455,858, of whom approximately 150,000 resided in the capital and largest city of Bandar Seri Begawan. Its official language is Malay and Islam is the state religion of the country, although other religions are nominally tolerated. The government of Brunei is an absolute monarchy ruled by the Sultan of Brunei, and it implements a fusion of English common law and jurisprudence inspired by Islam, including sharia.