The Isle of Man ( /ˈmæn/; Manx: Ellan Vannin, pronounced [ˈɛlʲən ˈvanɪn]), otherwise known simply as Mann (Manx: Mannin, IPA: [ˈmanɪn]), is a self-governing Crown Dependency of the United Kingdom, located in the Irish Sea between the islands of Great Britain and Ireland, within the British Isles. The head of state is Queen Elizabeth II, who holds the title of Lord of Mann. The Lord of Mann is represented by a Lieutenant Governor. The island is not part of the United Kingdom, but its foreign relations and defence are the responsibility of the UK Government. Although the United Kingdom does not usually interfere in the island's domestic matters, its "good government" is ultimately the responsibility of the Crown (that is, in practice, the Government of the United Kingdom).

The island has been inhabited since before 6500 BC. Gaelic cultural influence began in the 5th century AD, and the Manx language, a branch of the Gaelic languages, gradually emerged. In the 9th century, the Norse began to settle there. A Norse-Gaelic culture arose and the island came under Norse control. In 1266, the island became part of Scotland as formalised by the Treaty of Perth. After a period of alternating rule by the kings of Scotland and England, the island came under the feudal overlordship of the English Crown in 1399. The lordship revested into the British Crown in 1764 but the island never became part of Great Britain or its successor the United Kingdom and retained its status as an internally self-governing Crown dependency.