Explicit systematic phonics instruction is more effective for native English-speaking children learning to read and write than non explicit phonics instruction (National Institute of Child Health and Human Development, 2000). This study goes beyond native speakers, and explores the effects that systematic and explicit phonics instruction has on young students learning English as a Foreign Language (EFL). Moreover, phonics instruction for EFL students was differentiated: the instructional time, instructional sequence and phonics vocabulary were adapted to meet EFL students' needs. The findings show that, not only does explicit and differentiated phonics instruction have a positive effect for EFL learners in reading comprehension, but also that the differentiation of it has a considerable impact on EFL students literacy skills in general.