This paper describes how five classroom teachers make sense of their role as mentors in support of novices as they learn to teach. These teachers interact within a context that provides possibilities for participation with a teacher education program and professional development research. The main aim of the study was to gain insights into ways in which the five mentors talk about their theories of how novices learn to teach, use different sources of knowledge to help novices learn to teach, and model and encourage critical reflection about issues and practices in teacher education. Findings reveal that four of the five mentors played prominent roles as teacher educators, and developed collaborative relationships within the professional development school context between mentors, prospective teachers, and university faculty through sustained interactions, shared professional responsibility, and respect.