This article reviews the literature on the relatively new field of materials development for language learning and teaching. It reports the origins and development of the field and then reviews the literature on the evaluation, adaptation, production and exploitation of learning materials. It also reviews the literature, first, on a number of controversial issues in the field, next, on electronic delivery of materials and, third, on research in materials development. It identifies gaps in the literature and makes proposals for future progress in materials development and in the research within the field. Much of the literature focuses on materials for learning English but the same principles apply to materials for learning any L2, as has been acknowledged by some of the authors whose publications focus on materials for learning other languages.