This article presents an initial review of research (published in English) on the impact, internationally, of English as an additional language (EAL) provision in the school sector. The impact is on English language learners (ELL): children and young people for whom English is an additional language and who are thought to need extra help with English to succeed in the school system. The review looks not only at the impact on children and young people, but also at the nature and efficacy of the teacher workforce, concluding that there are several gaps in provision and in research in the field.