This article reports on a year-long study of collaborative professional learning in a mentor teacher study group connected to a large university teacher education program. It introduces a theoretical framework for considering the nature of interactive talk and its relationship to professional learning. Using examples of study group discourse, it then presents a methodology for analyzing interactive talk and the joint construction of ideas about practice. The article concludes by describing study group materials and analytic tasks developed from artifacts of practice, and offering an analysis of leadership and facilitation issues for guiding inquiry-oriented discourse in study group contexts.