The British Indian Ocean Territory (BIOT) is an overseas territory of the United Kingdom situated in the Indian Ocean. The territory comprises the seven atolls of the Chagos Archipelago and is located about halfway between Africa and Indonesia.

Established as a British territory in 1965, the BIOT is home to the joint UK-US naval support facility, Diego Garcia, which plays a strategic role in global security. The Chagossians, the original inhabitants of the islands, were forcibly removed by the British government in the 1960s to make way for the military base, sparking controversy and legal disputes.

The BIOT is unique in that it does not have a permanent civilian population, and access to the territory is heavily restricted. The islands are known for their rich marine biodiversity and are designated as a Marine Protected Area to preserve the unique ecosystems.