Professional development is important for all teachers, and in low socio-economic schools where the challenges of teaching are greater this need is crucial. A model involving a combination of one-on-one peer mentoring integrated with group peer mentoring was piloted with experienced mathematics teachers of senior students in low socio-economic schools. The results of the study highlight the benefits of this model and identify key factors necessary for successful implementation. In particular, these factors were selection of partners, time, trust, developing a clear structure around the goals, building a relationship, and meeting regularly as a collective group. (Contains 1 table.)