national flag consisting of a blue field (background) with a yellow-bordered red diagonal stripe running from the lower hoist to the upper fly corner and, in the upper hoist corner, a yellow star. The flag's width-to-length ratio is 2 to 3.

In the late 19th century European powers sought to extend control inland from the coastal territories they had previously seized in central Africa. Under the controlling influence of King Leopold II of Belgium, the Association Internationale Africaine was established, which proclaimed the Independent State of the Congo (or Congo Free State) in 1885. Its flag, dating from 1877, was blue with a gold star symbolizing a shining light in the “Dark Continent.” The United States was the first to recognize the state and its flag. On June 30, 1960, its successor state (the Belgian Congo) became an independent country, and six yellow stars were added along the hoist of the flag to represent the six provinces. When the number of provinces was altered in 1963, the first flag was replaced by one with a yellow-bordered red diagonal stripe and, in the upper hoist corner, a larger yellow star (the flag design was slightly altered in 1966).

Kabila's son Joseph became president following the assassination of his father in 2001. After the younger Kabila had brought a measure of stability to the country, he proclaimed the country's “Third Republic” on February 18, 2006. The national flag of 1963–66 again became official, though the field was a lighter shade of blue.