This paper provides an account of a school-centred research and development project aimed at improving teacher and pupil understanding of talk as a tool for learning. The paper establishes the basis for a dialogic pedagogy and reflects on strategies for creating an effective classroom climate that promotes productive and purposeful talk. It goes on to explain how a collaborative approach, founded on the use of classroom-based research for professional development, was developed to encourage discussion and dissemination of practice amongst teachers across subject departments. In the classroom-based research a pragmatic approach was adopted, involving mixed-method data collection and analysis; this included video analysis of lessons, interviews and research logs to encourage reflective practice amongst teachers. This project suggests that the approach was highly successful in developing a staff as a community of learners and suggests that an approach which involves the collaborative analysis of classroom practice can lead to significant whole-school developments. The case is made for promoting a whole-school focus on the use of talk for learning and proposals for further developments are outlined. (Contains 2 figures, 2 tables and 2 notes.)