The induction phase plays a key role in shaping the professional identity of the teacher, so it is important that the beginning teacher has good mentoring support during induction. Supervision can be useful for the development of mentoring skills because it enables beginning mentors to build their professional identity and competencies through the integration of their practical experience and theoretical knowledge. In the case of beginners in a profession (in this case beginning mentors), method-oriented supervision can be especially beneficial because of the emphasis on educational component. Method oriented supervision can help mentors to clarify their expectations, become aware of their own professional competencies, improve their interpersonal skills and clarify doubts they encounter in working with beginning teachers. Therefore, the aim of this action research was to explore the possibility of applying supervision in the development of competencies of beginning teachers’ mentors and to develop a model of method-oriented supervision. To make sure that the proposed model meets the needs of beginning teachers’ mentors, the first part of the research consisted of the content analysis of the teacher induction legal frame and of the focus groups of experienced mentors, beginner mentors and beginning teachers. As a result of this part of the research, the characteristics of the induction phase and the competencies of mentors necessary for successful mentoring were identified together with the key topics relevant to the development of mentors' competencies. These results were used as a basis for the development of the model of method-oriented supervision organized around the following topics: roles and responsibilities of mentors and beginning teachers, induction process, working alliance, experiential learning, communication skills and counselling skills. In the second part of the research, this program was applied with a supervision group consisting of five beginning teachers’ mentors. Based on the activity of supervisees during the process of method-oriented supervision and the reflections of the supervisor, it can be concluded that beginner teachers’ mentors developed educational mentoring approach. They also improved their observational skills and skills needed for establishing a working alliance with beginner teachers. It can be concluded that the proposed model of method-oriented supervision has proven to be useful for the development of the competencies of the beginning teachers’ mentors.