Recent discussion has focused on the benefits and constraints of using and teaching reflection for professional self-development (Farrell, 2007; Volk, 2010). Alongside this is an interest in the value of dialogue in teacher development (for example Edge, 2007). This paper describes the experience of advanced language teachers participating in a reflective practice project undertaken as a paper in a professional master’s qualification in a New Zealand tertiary institution. Using data from teacher participant reflective essays and an end of course evaluation, the paper describes teachers’ growth in reflectivity and notes the role of dialogue in promoting professional development. The paper also explores the extent to which Stanley’s framework (1998) was useful in measuring levels of reflectivity. The researchers found that teachers believed the course promoted their professional development in several ways, and that the activities participants found most helpful were ones that contained an element of dialogic interaction. Participants’ level of reflectivity at the end of the course was high on Stanley’s (1998) framework, but it was necessary to modify parts of the framework for use in this context.