THE DEVELOPMENT OF ‘WORKING THEORIES’ is a key learning outcome for New Zealand's early childhood curriculum Te Whāriki (MoE, 1996, p. 44). Working theories are described as combinations of knowledge, skills and attitudes which support children's developing understanding of the world, and guide their actions, problem solving and learning. This article reports research into the working theories of a group of children in one early childhood setting, and argues that working theories serve a variety of purposes linked to effective action within children's specific sociocultural contexts. This, and the fact that the social and cultural context provides resources with which children construct working theories, is used to argue a case for sociocultural pedagogies to support children in creating and modifying working theories. A case study is provided from the author's research. With recognition that the implementation of sociocultural pedagogies is somewhat difficult for early childhood practitioners (Anning, Cullen & Fleer, 2004), the article offers some specific strategies related to supporting children's working theories.