Research in English as a Lingua Franca (ELF), that is the medium of communication between people who come from different linguacultural backgrounds, has created a rich body of work in various areas. This article focuses on a more recent development of this research for teachers and teacher educators in the perspective of critical language education (CLE). We explore how ELF research, both the linguistic/discourse-oriented one and the pedagogic-oriented one, can benefit from its links to CLE, with its understanding of teaching for social change. We then refer to aspects of critical transformative theory that become relevant in designing and implementing ELF-aware teacher education programmes, focusing especially on three recursive (non-linear) components, i.e. the phase of exposure, the phase of critical awareness and the phase of development of actions that teachers can implement in their teaching. We finish by exploring the critical role of assessment in language education and conclude by inviting teachers and educators to become involved in ELF research for CLE.