 In June 1968, Dwyer reported to the Republic of Vietnam, and was assigned as the CO, 1st Marines, 1st Marine Division (Reinforced), FMF.He was promoted to brigadier general on August 14, 1968, and subsequently served as assistant division commander, 1st Marine Division; Commanding General (CG) Task Force Yankee, 1st Marine Division; and finally as G-3, III Marine Amphibious Force.Following his return to the States in late June 1969, Dwyer commanded the 5th Marine Division until it was deactivated in December 1969.