The importance of teacher motivation for language teachers and their learners is increasingly being recognised in numerous worldwide contexts, where unfortunately low teacher motivation is also commonly a cause for concern. Yet teacher motivation is a curiously neglected topic in the literature on second language teacher education (SLTE). Building on the research that has been conducted in general education, and in studies of the motivation of second language learners, this chapter first presents a theoreticization of SLTE. After reviewing key findings from this emerging field of research, it then considers how they can inform the practice of teacher educators in both pre-service and in-service settings. A key argument made is that protecting and enhancing teacher motivation should be an inherent goal of SLTE. Understanding the nature of participating teachers’ motivation is crucial in itself, since this understanding will help teacher educators determine whether participating teachers are likely to benefit from the processes of SLTE on offer, and if not, which alternative continuing professional development activities might be more successful. Practical suggestions are made and key readings are provided.