The 3rd Division of the Army of the Republic of Vietnam (ARVN)—the army of the nation state of South Vietnam that existed from 1955 to 1975—was part of the I Corps that oversaw the northernmost region of South Vietnam, the centre of Vietnam.

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.