There is increasing agreement among those who study classrooms that learning is likely to be most effective when students are actively involved in the dialogic coconstruction of meaning about topics that are of significance to them. This article reports the results of an extended collaborative action research project in which teachers attempted to create the conditions for such dialogue by adopting an inquiry approach to the curriculum. A quantitative comparison between observations made early and late in the teachers' involvement in the project showed a number of significant changes in the characteristics of teacher-whole-class discourse, with a shift toward a more dialogic mode of interaction. Nevertheless, the initiation-response-follow-up (IRF) genre continued to be pervasive. Despite this, when the same observations were examined qualitatively, there was clear evidence of an increase over time in the teachers' adoption of a "dialogic stance." The article concludes with a consideration of the relationship between the choice of discourse formats and the enactment of a dialogic stance.