Each of the approaches is designed to deal with delinquents who have varying developmental capabilities and problems. Group counseling focuses on a particular type of problem--social, educational, vocational, or personal. It usually takes place in school, human service agency, clinic, and institutional settings. Group psychotherapy, on the other hand, is designed to promote personality and behavior change through interaction in a carefully structured environment that is influenced strongly by the therapist. The behavior therapy model, which assumes that all behavior is learned through reinforcement and that the principles of social learning can be applied to individuals to produce behavioral changes, establishes behavioral objectives for the group as a whole (in addition to individual goals). Reality therapy, a variant of the behavior therapy model, maintains that delinquents are personally responsible for their own behavior and that by examining it and making value judgments about it, the youth can achieve a 'success identity.' Guided Group Interaction directs the dynamics and strengths of the peer group toward constructively altering and developing group members' behavior. Consisting on the average of 10 members, lasting from 4 to 6 months, the group is most effective for the adaptive offender, the individual who becomes involved with delinquency in association with others. Important aspects of the group structure are the number, frequency, and length of group meetings; open-ended vs. closed; the degree of therapist control; and the meeting format. The group process can be viewed in terms of the amount and type of the group leader's participation; the extent to which themes are introduced by the group leader or emerge from the members; the definition of group operations (group or individually oriented); the degree of analytic orientation; and the degree to which an accepting climate is generated and maintained or to which confrontation is emphasized. The developmental process of the group is divided into four phases, each phase described in terms of the major problems confronting the group and the characteristic behavior found at each phase. Twenty-four references are provided.