In September 1966, the White Knights deployed to the Republic of Vietnam, where they were assigned to Marine Aircraft Group 36, 1st Marine Aircraft Wing. From October 1966 to August 1969, the squadron operated from Kỳ Hà, Hue/Phu Bai, , , Marble Mountain area near Da Nang, and from . On June 6, 1968, HMM-165 had two of their CH-46As shot down in the vicinity of Khe Sanh. There were no deaths on the first incident but the second crash which occurred at LZ Loon, southeast of Khe Sanh, resulted in the death of 12 of the 23 Marines on board.