The terminology of the British Isles comprises the words and phrases that are used to describe the geographical and political areas of the islands of Great Britain, Ireland, and the smaller islands which surround them. The terms are often a source of confusion, partly owing to the similarity between some of the actual words used but also because they are often used loosely. Many of the words carry geographical and political connotations which are affected by the history of the islands.

The Crown Dependencies are three offshore island territories in the British Islands that are self-governing possessions of the British Crown: the Bailiwick of Guernsey and the Bailiwick of Jersey, both located in the English Channel and together known as the Channel Islands, and the Isle of Man in the Irish Sea between Great Britain and Ireland.