Reflective models of supervision have shifted the emphasis from teaching observations as primarily evaluative events to events intended to promote teachers' reflective practice. This paper presents a longitudinal action research study investigating post-observation interactions between language teachers and their supervisors in an American university English Programme. The longitudinal design, data collection and analysis were ongoing and recursive, allowing each to inform the other at various stages of the study. The authors/researchers were also the supervisors/participants in the study, and were interested in improving existing practices based on an analysis of available data. A preliminary analysis revealed that the supervisors produced the majority of the talk in the meetings and that the teachers were more passive. Focussing primarily on data from four teacher/supervisor pairs from two semesters, we describe how this study enabled supervisors to become aware of the linguistic and interactional subtleties of their practices in post-observation meetings. We then illustrate how supervisors changed the meeting dynamics from supervisor-centred to more teacher-centred. We describe changes in the distribution of talk and discuss how and why these changes took place. We also illustrate important changes in the ways that teachers were positioned by supervisors in the opening of meetings.