Children have been employed as behavior therapists in intervention programs with peers. Peer mediated interventions are described as those having an indirect influence no the behavior of target children and those having a more direct influence. Research examining peer mediation of a direct nature is presented and evaluated. The experimental studies reviewed are divided into three major areas: (1) peers as tutors; (2) peers as reinforcing agents; and (3) peers as facilitators of generalization. Conclusions, clinical applications, and future directions follow.