The Vietnamese Rangers (Vietnamese: Biệt Động Quân), commonly known as the ARVN Rangers or Vietnamese Ranger Corp (VNRC), were the light infantry of the Army of the Republic of Vietnam. Trained and assisted by American Special Forces and Ranger advisers, the Vietnamese Rangers infiltrated beyond enemy lines in search and destroy missions. Initially trained as a counter-insurgency light infantry force by removing the fourth company each of the existing infantry battalions, they later expanded into a swing force capable of conventional as well as counter-insurgency operations, and were relied on to retake captured regions. Later during Vietnamization the Civilian Irregular Defense Group program was transferred from MACV and integrated as Border Battalions responsible for manning remote outposts in the Central Highlands.

The Army of the Republic of Vietnam composed the ground forces of the South Vietnamese military from its inception in 1955 to the Fall of Saigon in April 1975. At the ARVN's peak, an estimated 1 in 9 citizens of South Vietnam were enlisted, composed of Regular Forces and the more voluntary Regional Forces and the Popular Force militias. It is estimated to have suffered 1,394,000 casualties during the Vietnam War.