This chapter discusses the expertise framework and its potential to tap into cognition in translation and interpreting, especially from the perspective of an expert-performance approach to translation and interpreting. The major topics include: notions of expertise; expertise as consistently superior performance and the result of deliberate practice; expertise as a robust theoretical construct to investigate cognition in translation; the non-transference of expertise across domains; translator’s expertise as compared with field specialist’s expertise; implications of expertise studies in writing and reading for studies of expertise in translation; and implications of the notion of interactional expertise for the study of expertise in translation and interpreting. The chapter concludes with some challenges Cognitive Translation Studies will eventually need to address to gain a more comprehensive understanding of expertise in translation and interpreting.