Ruanda-Urundi, later Rwanda-Burundi, was a colonial territory, once part of German East Africa, that was occupied by troops from the Belgian Congo during the East African campaign in World War I and was administered by Belgium under military occupation from 1916 to 1922. It was subsequently awarded to Belgium as a Class-B Mandate under the League of Nations in 1922 and became a Trust Territory of the United Nations in the aftermath of World War II and the dissolution of the League. In 1962 Ruanda-Urundi became the two independent states of Rwanda and Burundi.

German East Africa was a German colony in the African Great Lakes region, which included present-day Burundi, Rwanda, the Tanzania mainland, and the Kionga Triangle, a small region later incorporated into Mozambique. GEA's area was 994,996 km2 (384,170 sq mi), which was nearly three times the area of present-day Germany and almost double the area of metropolitan Germany at the time.