Young children are keenly motivated to inquire into and make meaning about their worlds. This article discusses "working theories", one of two indicative learning outcomes of the New Zealand early childhood curriculum, "Te Whariki". Working theories occur as children attempt to find connections between their experiences and understandings to make sense of their worlds. The article proffers several sociocultural theoretical bases for understanding and developing this under-explored construct. Specifically, the concept of working theories is proposed as a way children connect, edit, extend and deal with new or discrepant pieces of knowledge in endeavours to build their understandings. To substantiate this argument, examples of children's working theories from a qualitative study of young children's interests and inquiries are provided. A "spiral of knowing" provides a concept to further theorise processes of children's knowledge connections and meaning making. Implications for early childhood teachers' knowledge and practice and future research are described.