A vertical tricolour of black, yellow an red from hoist to fly.
Prior to the Belgian invasion of the Ruanda-Urundi territory in the African great Lakes region in April 1916, the territory was part of German East Africa. Following the First World War, Belgium maintained a military occupation of the territory until 20 July, 1922 when it became a Class-B Mandate under the League of Nations. In 1945 following the dissolution of the League of Nations, Ruanda-Urundi became a Trust Territory of the United Nations. The territory remained under Belgian control until gaining independence on 1 July, 1962 resulting in the establishment of Rwanda and Burundi