Classroom materials play a major role in teachers' professional lives and are a central component of the English as a Foreign Language (EFL) classroom. Teachers themselves have been found to create and adapt materials for a plethora of reasons, one of which is their own continuing professional development. This article aims to take stock of a growing body of literature on teachers as materials developers. It will offer various perspectives on the why, what and how of materials development by teachers. In addition to theoretical discussions, the article presents empirical findings of a recent doctoral study (Bouckaert, 2017) which explored the potential value of this creative process for teachers' development of reflective practice. The article frames answers to the three who, what, where questions as it offers practical recommendations for teachers and those involved in language teacher education and training.