In South East Asia the Marxist message came primarily to address issues of nation-building. The article traces the development of communist parties from their early diasporic networks and engagement with the Comintern, to their relations with the colonial powers, to the establishment of communist-ruled states after the Second World War, through to the Cold War and US efforts to contain communism. The article looks at the various forms that communism took in the region, from hybrid Chinese associations in British Malaya and Hồ Chí Minh’s Indochina network, to the constitutional party of Sukarno’s Indonesia, to the semi-Buddhist Burmese Way to Socialism of Ne Win, to the neo-dynastic communism of Pol Pot. Special attention is paid to the interplay between nationalism, internationalism, and communism.