Literacy is a powerful tool against poverty, leading to further education and vocational success. In sub-Saharan Africa, schoolchildren commonly learn in two languages--African and European. Multiple early literacy skills (including phonological awareness and receptive language) support literacy acquisition, but this has yet to be empirically tested in sub-Saharan Africa, where learning contexts are highly multilingual, and children are often learning to read in a language they do not speak at home. We use longitudinal data from 1,100 school children spanning three groups of native languages [Mijikenda languages (Digo, Duruma, Chonyi, and Giriama), Kiswahili, Kikamba] in coastal Kenya (language of instruction: Kiswahili and English). We find that baseline phonological awareness and receptive language are differentially important in predicting literacy skills in English and in Kiswahili, and these relations are moderated by the degree of shared cross-linguistic features between home and school languages. Importantly, the relative importance of these factors changes over development. Implications for language development and literacy acquisition in linguistically diverse contexts are discussed.