The relationship between indigenous groups and the Argentine state has been complex throughout history. In the framework of a state schooling model that did not recover the knowledge and experience of indigenous peoples, various churches defended their own interests, and replaced, challenged and supported State’s tasks. This paper discusses the links between the (Catholic and Protestant) churches and indigenous peoples, focusing on education, particularly on literacy process. We systematize actions that, for various purposes, sought to promote the oral and written use of the official state language by the tobas/qom and mbya-guaraní people (northern and northwestern Argentina), as well as facilitate the development of the writing of indigenous languages. In many cases and even with contradictions, these actions represent an understudied precedent of intercultural school education. Methodologically, documentary sources and theoretical analyzes are recovered in light of ethnographic field explorations made in the last decade with those populations.