1957 in the Vietnam War

May

 * May 8 - 19

As part of his Ngo Dinh Diem presidential visit to the United States Diem arrived at noon on May 8 at the National Airport in Washington, D.C. aboard the plane of U.S. President Dwight D. Eisenhower, the Columbine III, a silver Constellation. Diem's plane landed and he was personally received at the airport by Eisenhower, Secretary of State John Foster Dulles and Chairman of the Joint Chiefs of Staff Nathan Twining. It was only the second time that Eisenhower had personally gone to the airport to greet a visitor as president.

July
Anti-government guerrillas kill 17 people in a bar during the Chau Doc massacre. The killing are part of a low level campaign targeting government officials, school teachers, village chief's families.
 * July 11

September
The Ngo Dinh Diem presidential visit to Australia from 2 to 9 September 1957 was an official visit by the first President of the Republic of Vietnam.
 * September 2-9

December
Russian and Chinese ministers Nikita Khrushchev and Chou Enlai decide that South and North Vietnam should be regarded as separate countries and each have a seat at the United Nations. This forces the North Vietnam government to strive for a military solution to unite North and South Vietnam.