This paper focuses on the role of collaboration in facilitating critical reflection and interpretation of data in a collaborative research project undertaken by school-based and university-based researchers. The popular image of research in the natural and social sciences has long been dominated by the figure of the lone researcher, but this image is contrary to the very social nature of the research process and renders invisible the researcher's connections to the participants and others who make valuable contributions. As researchers begin to deconstruct their own research practices, they begin to see how the social and collaborative interactions shape their outcomes. This paper provides an overview of the nature of the collaborative research project, discusses the reality of collaborative research, and explores the role of collaboration in critical reflection, interpretation, and the co-construction of professional knowledge. The research project that provides the context for the discussion was a qualitative and collaborative study of four early-years teacher-researchers who work with children from diverse family contexts. The ongoing research project is exploring teachers' talk about and critical reflections on their own investigations of the home literacies and "funds of knowledge" of a small group of students. The study also brought the power of collaboration in the generation of new professional knowledge into the foreground. (Contains 52 references.) (SLD)