Mentoring programs for youth have become increasingly popular interventions and are generally effective in promoting proteges' wellbeing and functioning. Building on recent efforts to understand the interpersonal mechanisms underlying mentoring relationships, the authors apply central concepts from attachment, social support and social learning theories and systematically compare the mentor's role with the roles of other caregivers (parent, therapist, friend, teacher). The authors highlight similarities and differences between mentoring and these roles, and discuss interpersonal dynamics specific to each relationship that can be enacted in mentoring. It is argued that the uniqueness of mentoring rests on mentors' ability flexibly to transverse these different roles to some degree, without embodying any. Consequently, the authors underscore the existence of different profiles of mentoring relationships and suggest that these might address diverse proteges' needs. This view serves to articulate specific recommendations for research and practice in light of protege heterogeneity. (Contains 1 figure.)