North Korea

North Korea in Vietnam War: As a result of a decision of the Korean Workers' Party in October 1966, in early 1967 North Korea sent a fighter squadron to North Vietnam to back up the North Vietnamese 921st and 923rd fighter squadrons defending Hanoi. They stayed through 1968, and 200 pilots were reported to have served.

In addition, at least two anti-aircraft artillery regiments were sent as well. North Korea also sent weapons, ammunition and two million sets of uniforms to their comrades in North Vietnam. Kim Il-sung is reported to have told his pilots to "fight in the war as if the Vietnamese sky were their own".

Cuba

Cuba in Vietnam War: The extent of manpower contributions to North Vietnam by the communist Republic of Cuba, under Fidel Castro, is still a matter of debate. Then and since, the communist Vietnamese and Cuban governments have not divulged any information on this matter. There are numerous reports by former U.S. prisoners of war that Cuban military personnel were present at North Vietnamese prison facilities during the war, and that they participated in torture activities, in what is known as the "Cuba Program". Witnesses to this include Senator John McCain, 2008 U.S. Presidential candidate and former Vietnam prisoner of war, according to his 1999 book Faith of My Fathers. That there was at least a small contingent of Cuban military advisors present in North Vietnam during the war is without question. Some, notably Vietnam War POW/MIA issue advocates, claim evidence that Cuba's military and non-military involvement may have run into the "thousands" of personnel.