British Indian Ocean Territory

• The British Indian Ocean Territory Order and Ordinances made by the Commissioner
• English law, as applied by those Ordinances
• International law, including the International Court of Justice's advisory opinion of 2019 on the separation of the archipelago from Mauritius

• A Supreme Court and a Magistrate's Court for the territory, with judges who sit outside the islands
• Cases challenging its laws have been heard in the courts of England and Wales, up to the House of Lords (now the UK Supreme Court)
• Appeals from its own courts follow the arrangements for British Overseas Territories

There is no resident legal profession. English lawyers handle the cases that arise.

• The territory has no permanent civilian population, apart from military and support staff.
• The former inhabitants, the Chagossians, have brought many cases in the English courts.
• The International Court of Justice has stated its view on the lawfulness of the separation from Mauritius.

Mauritius, United Kingdom, Seychelles, Maldives, Falkland Islands

The University of Ottawa’s JuriGlobe database lists British Indian Ocean Territory as: Common law. It names the systems in order of importance.

The map colours a country by the first-named system, and shows both civil-law and common-law countries as “mixed”. It is a simplification, and real systems are rarely pure.

Antigua and Barbuda, Australia, Bahamas, Barbados, Belize, Canada, Cook Islands, Dominica, Fiji, Ghana, Grenada, India, Ireland, Jamaica.

• JuriGlobe: world legal systems (University of Ottawa)

Sources last reviewed: October 2026.