In this study, a two-dimensional model of mentor teacher roles in mentoring dialogues, entitled MERID, is explored empirically. Data regarding five aspects of mentoring dialogues were collected, using a sample of 20 transcriptions of mentoring dialogues, in which 112 topics were discussed and 440 mentor teacher utterances emerged. Correlations between the five aspects were determined and a cluster analysis was conducted. There is empirical support for the model and it is a useful framework to promote reflection on mentor teachers' supervisory behaviour. (Contains 4 figures and 5 tables.)