Great Britain (Welsh: Prydain Fawr, Scottish Gaelic: Breatainn Mhòr, Cornish: Breten Veur, Scots: Great Breetain), also known as Britain, is an island to the north-west of Continental Europe. It is the ninth largest island in the world, the largest European island and the largest of the British Isles. With a population of about 60.0 million people in mid-2009, it is the third most populous island in the world, after Java and Honshū. It is surrounded by over 1,000 smaller islands and islets. The island of Ireland lies to its west. Politically, Great Britain also refers to the island itself together with a number of surrounding islands, which constitute the territory of England, Scotland and Wales.

All of the island is territory of the sovereign state of the United Kingdom of Great Britain and Northern Ireland, and most of the United Kingdom's territory is in Great Britain. Most of England, Scotland, and Wales are on the island of Great Britain, as are their respective capital cities: London, Edinburgh, and Cardiff.