Three Southeast Asian polities, Cambodia, Laos and Thailand share much of their geography, history, culture, religion and language. Not all speakers of more than 100 languages spoken in the area have a sufficient knowledge of the respective national languages, Khmer, Lao and Thai. Yet, for the most part, the national languages are the only languages of literacy or the media of instruction in education. This paper discusses language planning for literacy in these three polities. The focus is on literacy in local minority languages. The paper also compares the similarities and differences in approaches of providing literacy and basic education to ethnic minority populations. It argues that in all three polities literacy is conceptualised as a process tied to the standardised national language. Recently, however, some local level initiatives in Cambodia and Thailand have started changing such conceptualisation. (Contains 5 tables and 4 figures.)