The national flag of the Lao People's Democratic Republic (Lao: ທຸງດວງເດືອນ, RTGS: thung duang duan, meaning 'Moon flag') consists of 3 horizontal stripes, with the middle stripe in blue being twice the height of the top and bottom red stripes. In the middle is a white disc, the diameter of the disc is 4⁄5 the height of the blue stripe. The flag ratio is 2:3. The flag was first adopted in 1945 under the Lao Issara government of 1945–46, then by the Pathet Lao.

From 1973 to 1975, the Pathet Lao formed part of the government coalition before assuming power directly and prompting the abdication of the king. Their flag was subsequently adopted as the national flag. According to the original creator of the flag, Maha Sila Viravong, the white disk in the center symbolizes the unity of the Lao people (and the future reunification of the two Laotian regions—Laos and northeastern Thailand—divided by the Mekong River) under one nation. It is also said to represent a full moon over the Mekong River.

The red stripes represent the blood shed by the Lao people on both banks of the Mekong River (including the multi-ethnic people of Laos and the Isan people of Northeastern Thailand) in their struggle for freedom and independence from the French, while the blue symbolizes the Mekong River itself, a symbol of the nation’s prosperity. Wikipedia