Saint Helena, Ascension and Tristan da Cunha is a British Overseas Territory located in the South Atlantic and consisting of the island of Saint Helena, Ascension Island, and the archipelago of Tristan da Cunha. Its name was Saint Helena and Dependencies until 1 September 2009, when a new constitution came into force, giving the three islands equal status as three territories, with a grouping under the Crown.

The British Overseas Territories (BOTs) are the 14 territories with a constitutional and historical link with the United Kingdom that, while not forming part of the United Kingdom itself, are part of its sovereign territory. The permanently inhabited territories are delegated varying degrees of internal self-governance, with the United Kingdom retaining responsibility for defence, foreign relations and internal security, and ultimate responsibility for good governance. All of the territories are inhabited by civilians, except three that are chiefly or only inhabited by military or scientific personnel. All fourteen have the British monarch as head of state. These UK government responsibilities are assigned to various departments of the Foreign, Commonwealth and Development Office and are subject to change.