This paper presents evidence on literacy trajectories for children in Ghana who enrolled in a Complementary Basic Education programme taught in mother tongue and transitioned into government schools. At the point of transition, we find that children who enrolled in government schools where the language of instruction differed from instruction in their mother tongue did not perform as well in literacy. After a year in government schools, those taught in another local language caught up. By contrast, those who transitioned into English did not. Our evidence reinforces the benefits of mother tongue and local language instruction for progress in literacy.