The Laotian Civil War was a civil war in Laos which was waged between the Communist Pathet Lao and the Royal Lao Government from 23 May 1959 to 2 December 1975. It is associated with the Cambodian Civil War and the Vietnam War, with both sides receiving heavy external support in a proxy war between the global Cold War superpowers. It is called the Secret War among the CIA Special Activities Center and Hmong and Mien veterans of the conflict.
The Kingdom of Laos was a covert theater for other belligerents during the Vietnam War. The Franco–Lao Treaty of Amity and Association transferred remaining French powers to the Royal Lao Government, establishing Laos as an independent member of the French Union. However, this government did not include representatives from the Lao Issara anti-colonial armed nationalist movement.
The following years were marked by a rivalry between the neutralists under Prince Souvanna Phouma, the right wing under Prince Boun Oum of Champassak, and the left-wing Lao Patriotic Front under Prince Souphanouvong and half-Vietnamese future Prime Minister Kaysone Phomvihane.