The Vietnamese Demilitarized Zone was a demilitarized zone at the 17th parallel in Quang Tri province that was established as the dividing line between the two countries i.e. North Vietnam and South Vietnam from 22 July 1954 to 2 July 1976 when Vietnam was officially divided into the two military gathering areas, which was intended to be sustained in the short term after the First Indochina War.

A demilitarized zone is an area in which treaties or agreements between states, military powers or contending groups forbid military installations, activities, or personnel. A DZ often lies along an established frontier or boundary between two or more military powers or alliances. A DZ may sometimes form a de facto international border, such as the Korean Demilitarized Zone. Other examples of demilitarized zones are a 14 km (8.7 mi) wide area between Iraq and Kuwait; Antarctica ; and outer space.