Cuba embraced an active internationalist foreign policy, also regarding protest movements by explicitly staging the Cuban and the Vietnamese struggles as parallel victims of US imperialism, most famously in Che Guevara鈥檚 鈥淢essage to the Tricontinental鈥. This talk examines the beginnings, development, and decline of global Vietnam solidarity and war protest. It outlines the context in which it emerged from the original protests in South Vietnam and how these were received globally. The decisive driving force were the decolonisation struggles of the Global South. The main section of this talk will focus primarily on international organisations such as the World Peace Council (WPC), its offshoot, the Afro-Asian People鈥檚 Solidarity Organisation (AAPSO), and the Organisation of Solidarity with the Peoples of Asia, Africa, and Latin America (OSPAAAL), in which socialist states and organisations played the decisive role. They coordinated and sustained protests and served as discussion forums for activists from all over the world. At the same time, these organisations were riddled with lines of internal conflict and ideological tensions emanating from competing visions of 鈥淭hird Worldism鈥 against the backdrop of the Sino-Soviet split. Vietnam solidarity formed the lowest common denominator in many respects. Finally, this contribution will show that after the Vietnamese occupation of Cambodia in December 1978 and the revelations of the Cambodian genocide, the relative cohesion of Vietnam solidarity could no longer be maintained.