Although there are many social skills and interventions available for professionals and parents to teach children with autism spectrum disorder (ASD), none focus on sibling relationships and utilize the playmate role of siblings for children with ASD to establish a better sibling relationship. The purpose of this book is to introduce a sibling as a playmate for social interaction intervention for children with ASD. It aims to appeal to a broad audience of practitioners who provide services to children with ASD and/or families of a child with ASD with a solid research based instructional curriculum. The book is based on the previous research studies on the child-mediated social intervention for children with ASD; those results have indicated the positive impact not only on increased social initiations and responses of children with ASD, but also on the higher occurrences of interactions between children with ASD and their typically developing siblings and peers. With adequate support, siblings of children with ASD not only play and/or interact with their brothers or sisters with ASD to learn appropriate social skills, but they also gain confidence for being helpful and skillful in building a positive sibling interaction and relationship with their brothers or sisters with ASD. The central goal of this book is two-fold: (1) To address how a positive sibling relationship could be established and become a buffer factor to the stresses and impacts of autism on family ecology, and (2) to present a comprehensive intervention on siblings as the agents of social change in order to support positive sibling interactions between children with ASD and their typically developing siblings.