German South West Africa (German: Deutsch-Südwestafrika) was a colony of the German Empire from 1884 until 1915, though Germany did not officially recognise its loss of this territory until the 1919 Treaty of Versailles. With a total area of 835,100 km², it was one and a half times the size of the mainland German Empire in Europe at the time. The colony had a population of around 2,600 Germans.

German rule over this territory was punctuated by numerous rebellions by its native African peoples, which culminated in a campaign of German reprisals from 1904 to 1908 known as the Herero and Namaqua genocide.

In 1915, during World War I, German South West Africa was invaded by the Western Allies in the form of South African and British forces. After the war its administration was taken over by the Union of South Africa (part of the British Empire) and the territory was administered as South West Africa under a League of Nations mandate. It became independent as Namibia on 21 March 1990.