Autism Spectrum Disorder (ASD) is experienced in a variety of ways within families particularly among siblings with and without ASD. The effects of ASD on sibling relationships are integral to family life. While some studies have examined sibling relationships, research regarding sibling roles exhibited during play activities and social interactions is lacking. Further, siblings' voices are rarely revealed in research on play. In response to a need for greater understanding of the role of play among siblings impacted by ASD, this dissertation used a cultural historical activity theory lens to understand how play and social interactions evolved among siblings since childhood development is informed by access to and participation in play. Siblings may be considered actors with unique cultural histories as they create and re-create their own identities through play. In this study, an emphasis was placed on the complex processes siblings experience while locating their own niche with their families. The study focused on the use of a variety of tools, division of labor, the rules families utilized to interact and how these rules were disturbed. As a result, the study offers a more complete understanding of how play and social interactions affect the ways ASD impact siblings, families, and community members. This study provides holistic views of the development and impact of sibling play on identity development and relationships.