Induction programmes for newly-qualified teachers generally involve some combination of four interlocking components: a mentoring system; an expert system; a peer system and a self-reflective system (European Commission 2010). One activity that is commonly used in the mentoring system is lesson observation. This article presents a comparative analysis of post-observation conversations held by two mentor-teacher dyads as part of teacher induction in Ireland. The analysis focuses on how both mentors support the teachers in the construction of their professionality. Doing so requires the right blend of professional, social and personal support, and depends on a high level of awareness and expertise on the part of the mentor. The article identifies certain key differences in the approaches of both, asn makes the case that this kind of analysis offers much potential for the professional development of mentors.