Numerous studies around the world report that new teacher induction is particularly critical, with beginning teachers often dropping out of the profession. Coaching, such as that provided by a mentor, occupies a front-line position among the means that can support new teacher induction. But, to ensure fruitful support in terms of professional development for the beginner, the mentor must act with precaution and mobilize several support skills. This is one of the aspects documented in our doctoral research, conducted in the form of a multi-case study and using a qualitative/interpretative approach with four coach-beginner dyads from secondary education in Quebec.