This paper presents a flowsheet model describing the interpersonal process of adolescent identity formation in relation to peers and peer groups within a social-psychological context. The model describes a primary route, a secondary route, and a vicious circle as pathways toward identity formation in relation to peers and peer groups. In the primary route, individuals associate with a peer group. If accepted by the group and satisfied with their role in the group they will either comply with, identify with, or internalize the group's values, beliefs, and behaviors, and will possess an identity. Any route other than the primary route is a secondary route, and is assumed to involve more conflicts, frustrations, and trials. These are cases where the individual is either unsatisfied or not accepted and will seek a new group or try a new strategy with the same group. In the case of the vicious circle the individual is not accepted after many frustrating attempts, and will either (1) keep trying, (2) become an internally-motivatived prosocial loner or (3) become an antisocial "lone wolf". The model is likened to a production line with the final product being identity. The process is considered to be the same for female and male adolescents. (LLL)