From the abstract: "Peer-mediated intervention has become a primary education practice in programs for children and youth with autism spectrum disorder (ASD). This article traces the emergence of peer-mediated interventions from early laboratory studies to the extensive applied research in the field that has documented the efficacy of the practice. Interventions to affect attitudes of peers toward their classmates with ASD and ecological features of classrooms that promote peer social interaction are discussed as indirect but important approaches to promoting the social engagement of children and youth with ASD. Three types of peer-mediated approaches—peer initiation, peer-mediated social networks, and peer support—are identified as more direct approaches to promoting the social engagement of children and youth with ASD. The article concludes with a discussion of the role of peer-mediated interventions in increasing the attractiveness (reinforcement value) of peer interaction for children and youth with ASD."