The Tet Offensive was a military campaign during the Vietnam War that was launched on January 30, 1968. Regular and irregular forces of the People’s Army of Vietnam fought against the forces of the Republic of Vietnam (South Vietnam), the United States, and their allies. The purpose of the offensive was to utilize the element of surprise and strike military and civilian command and control centers throughout South Vietnam, during a period when no attacks were supposed to take place.
The operations are referred to as the Tet Offensive because there was a prior agreement to “cease fire” during the Tet festivities (Lunar New Year Celebrations). The Viet Cong broke the agreement, and launched an attack campaign that began during the early morning hours of 30 January 1968, on Tết Nguyên Đán. The main wave of attacks was carried out the next morning. Both North and South Vietnam announced on national radio broadcasts that there would be a two-day cease-fire during the holiday. In Vietnamese, the offensive is called Cuộc Tổng tiến công và nổi dậy (“General Offensive and Uprising”), or Tết Mậu Thân (Tet, year of the monkey).
The NLF launched a wave of attacks on the morning of 30 January in the I and II Corps Tactical Zones of South Vietnam. This early attack did not, however, cause undue alarm or lead to widespread defensive measures. When the main NLF operation began the next morning, the offensive was countrywide in scope and well coordinated, with more than 80,000 communist troops striking more than 100 towns and cities, including 36 of 44 provincial capitals, five of the six autonomous cities, 72 of 245 district towns, and the southern capital. The offensive was the largest military operation yet conducted by either side up to that point in the war.
The initial attacks stunned the US and South Vietnamese armies and took them by surprise, but most were quickly contained and beaten back, inflicting massive casualties on communist forces. During the Battle of Hue intense fighting lasted for a month and the NLF executed thousands of residents in the Massacre at Huế. Around the US combat base at Khe Sanh fighting continued for two more months. Although the offensive was a military defeat for the communists, it had a profound effect on the US government and shocked the US public, which had been led to believe by its political and military leaders that the communists were, due to previous defeats, incapable of launching such a massive effort.
The term “Tet offensive” usually refers to the January–February 1968 NLF offensive, but it can also include the so-called “mini-Tet” offensives that took place in May and August.