This chapter begins by identifying Sternberg and Horvath’s (1995) ‘expert teacher prototype’ as an appropriate, flexible framework for researching and describing teacher expertise. The framework serves as a means to identify the ‘family resemblances’ among expert teachers rather than as a checklist of necessary and sufficient features. The chapter then reviews previously used criteria for identifying teachers for expertise studies, with particular attention to Palmer et al.’s (2005) review of these. The majority of the chapter is devoted to reporting the findings of a comprehensive systematic literature reviews of prior empirical research into teacher expertise, identifying robust findings from studies investigating six aspects of teacher expertise: the knowledge base, cognitive processes, beliefs, personal attributes, professionalism and pedagogic practices of expert teachers. The chapter then discusses what is missing from this expert teacher prototype as researched to date, identifying particularly the strong Northern bias in this research and why this is problematic. It reports briefly on the only detailed study found that researched expert teachers in a Southern context (Toraskar, 2015), which, due to the methodological difficulties the author encountered, is of limited use only.