While for political, economic and social justice reasons, there is now an emphasis on ensuring that all children achieve educationally, including those whose ethnicity, "race" or socio-economic status are different from the dominant culture, multiple and often contradictory discourses operate concerning how teachers should work with diversity. Within post-structural theories, "race", socio-economic status, gender and ethnicity are theorised as fluid, dynamic and interconnected categories of identity. In this article, working with post-structuralist concepts including notions of "discourse", "subjectivities", and "investments", I briefly review a number of discourses around identities and difference that play out within education, particularly in Australia, but with reference to research in North America, and the United Kingdom as well. I then draw on research data to present a case study of one teacher's perspective on diversity. Using his childhood experiences of being both an "insider" and "outsider" in mainstream culture, I speculate on how his subjectivities shape and are shaped by his professional identity and relations with students. I discuss his understanding of diversity and of socially just pedagogies in light of current discourses and consider some implications for how teacher education might develop richer, more complex understandings of diversity. (Contains 4 notes.)