Under the Interpretation Act 1978 of the United Kingdom, the term British Islands refers to the United Kingdom of Great Britain and Northern Ireland, together with the Crown Dependencies: the Bailiwicks of Jersey and of Guernsey (which in turn includes the smaller islands of Alderney, Herm and Sark) in the Channel Islands; and the Isle of Man.

British Islands is a legal term that is not in general usage. It is not to be confused with the term British Isles.

The phrase "British Islands - Bailiwick of Jersey" is used, for example, on Jersey passports, replacing "United Kingdom of Great Britain and Northern Ireland" on the generally similar UK passport. (Both bear the inscription "European Union", although Jersey is in the customs union rather than the EU proper. A large proportion of Channel Islanders possess European Union citizenship by descent and are therefore entitled to EU passports - those Islanders with no inherited or acquired European Union citizenship have their passports stamped to this effect).