In this chapter we explore teachers’ perceptions of children’s diversity in different educational settings. Using interviews with teachers from Swedish preschools, preschool classes and the first grade in primary school, we aim to study transitions in school from the perspectives of several actors. The theoretical framework we employ is influenced by an ecological approach to understanding children’s needs in educational transitions. The teachers’ reflections on these three transitions emphasised the importance of context when responding to children’s needs. The teachers also described transitions as dynamic processes in which factors and conditions at different levels interact.