This chapter analyses some emerging perspectives on the social construction of teacher identities. Teacher identity has received little attention from a specifically social identity approach, but social identity theory is also heavily grounded in a meta-theory that sees identity as socially defined as well as socially embedded. The chapter focuses on social identity – is primarily to introduce a number of ways of exploring the nature of teacher identities from a post-structuralist perspective and to encourage readers from varied perspectives to look for new ways to ask questions of interest in this domain. In recent years, the conceptualisation of teachers’ identities has gathered increasing attention across a range of disciplinary fields. A reading of the basic tenets of post-structuralism and self-categorisation theory shows that the perspectives do share an important understanding of the phenomenal reality of the social world and its impact on the self-definitions.