Vietnamization was a policy of the Richard Nixon administration to end U.S. involvement in the Vietnam War through a program to "expand, equip, and train South Vietnamese forces and assign to them an ever-increasing combat role, at the same time steadily reducing the number of U.S. combat troops". Brought on by the Viet Cong's Tet Offensive, the policy referred to U.S. combat troops specifically in the ground combat role, but did not reject combat by the U.S. Air Force, as well as the support to South Vietnam, consistent with the policies of U.S. foreign military assistance organizations. U.S. citizens' mistrust of their government that had begun after the offensive worsened with the release of news about U.S. soldiers massacring civilians at My Lai (1968), the invasion of Cambodia (1970), and the leaking of the Pentagon Papers (1971).

The name "Vietnamization" came about accidentally. At a January 28, 1969, meeting of the National Security Council, General Andrew Goodpaster, deputy to General Creighton Abrams and commander of the Military Assistance Command, Vietnam, stated that the Army of the Republic of Vietnam (ARVN) had been steadily improving, and the point at which the war could be "de-Americanized" was close. Secretary of Defense Melvin Laird agreed with the point, but not with the language: "What we need is a term like 'Vietnamizing' to put the emphasis on the right issues." Nixon immediately liked Laird's word.Vietnamization fit into the broader détente policy of the Nixon administration, in which the United States no longer regarded its fundamental strategy as the containment of communism but as a cooperative world order, in which Nixon and his chief adviser Henry Kissinger were focused on the broader constellation of forces and the bigger world powers. Nixon had ordered Kissinger to negotiate diplomatic policies with Soviet statesman Anatoly Dobrynin. Nixon also opened high-level contact with China. U.S. relations with the Soviet Union and China were of higher priority than South Vietnam.

Nixon said Vietnamization had two components. The first was "strengthening the armed force of the South Vietnamese in numbers, equipment, leadership and combat skills", while the second was "the extension of the pacification program [i.e. military aid to civilians] in South Vietnam." To achieve the first goal, U.S. helicopters would fly in support; however, helicopter operations were too much part of ground operations to involve U.S. personnel. Thus, ARVN candidates were enrolled in U.S. helicopter schools to take over the operations. As observed by Lieutenant General Dave Palmer, to qualify an ARVN candidate for U.S. helicopter school, he first needed to learn English; this, in addition to the months-long training and practice in the field, made adding new capabilities to the ARVN take at least two years. Palmer did not disagree that the first component, given time and resources, was achievable. However: "Pacification, the second component, presented the real challenge...it was benevolent government action in areas where the government should always have been benevolently active...doing both was necessary if Vietnamization were to work."

The policy of Vietnamization, despite its successful execution, was ultimately a failure as the improved ARVN forces and the reduced American and allied component were unable to prevent the fall of Saigon and the subsequent merger of the north and south, to form the Socialist Republic of Vietnam.