South Georgia and the South Sandwich Islands (SGSSI) is a British Overseas Territory in the southern Atlantic Ocean. It is a remote and inhospitable collection of islands, consisting of South Georgia and a chain of smaller islands known as the South Sandwich Islands. South Georgia is 165 kilometres (103 mi) long and 35 kilometres (22 mi) wide and is by far the largest island in the territory. The South Sandwich Islands lie about 700 kilometres (430 mi) southeast of South Georgia. The territory's total land area is 3,903 km² (1,507 sq mi). The Falkland Islands are about 1,300 kilometres (810 mi) west from its nearest point.

The South Sandwich Islands are uninhabited, and a very small non-permanent population resides on South Georgia. There are no scheduled passenger flights or ferries to or from the territory, although visits by cruise liners to South Georgia are increasingly popular, with several thousand visitors each summer.

The United Kingdom claimed sovereignty over South Georgia in 1775 and the South Sandwich Islands in 1908. The territory of "South Georgia and the South Sandwich Islands" was formed in 1985; previously, it had been governed as part of the Falkland Islands Dependencies. Argentina claimed South Georgia in 1927 and claimed the South Sandwich Islands in 1938.

Argentina maintained a naval station, Corbeta Uruguay, on Thule Island in the South Sandwich Islands from 1976 until 1982 when it was closed by the Royal Navy. The Argentine claim over South Georgia contributed to the 1982 Falklands War, during which Argentine forces briefly occupied the island. Argentina continues to claim sovereignty over South Georgia and the South Sandwich Islands as part of the Tierra del Fuego, Antártida e Islas del Atlántico Sur Province.

Toothfish are vital to the islands' economy; as a result, Toothfish Day is celebrated on 4 September as a bank holiday in the territory.