The Civilian Irregular Defense Group was a military program developed by the Central Intelligence Agency (CIA) during the Vietnam War, which was intended to develop South Vietnamese irregular military units from indigenous ethnic-minority populations. The main purpose of setting up the CIDG program was to counter the growing influence of Viet Cong (VC) in the Central Highlands by training and arming the villagers for village defense. The program rapidly expanded after the US military transferred its control from CIA to MACV after two years since its inception and changed its focus from village defense to more conventional operations. From June 1967 onwards the CIDG members were made part of the Army of the Republic of Vietnam (ARVN) or other government agencies to increase Vietnamese participation. By late 1970, the remaining CIDG camps were converted to Vietnamese Rangers camps. The indigenous ethnic-minority people that formed the CIDG reaped significant benefits by the government of South Vietnam for their allegiance and it was the first time that minority groups were given full status as citizens of South Vietnam.

The siege of Plei Me was the beginning phase of the first major confrontation between soldiers of the North Vietnamese People's Army of Vietnam (PAVN) and the U.S. Army during the Vietnam War. The lifting of the siege by South Vietnamese forces and American air power was followed by the pursuit of the retreating North Vietnamese from 28 October until 12 November, setting the stage for the Battle of Ia Drang.