||The current study evaluated the effectiveness of a program developed for siblings of children with autism spectrum disorder. A total of 26 target siblings and their families participated in this study. The target siblings participated in a weekly, 2-hour intervention program, Siblings Helping Siblings, that lasted for 7 weeks. Components of this program included recreational activities as well as didactic lessons on problem-solving skills, coping strategies, and autism spectrum disorder. Outcome variables were measured at preintervention, postintervention, and 8-10 weeks following intervention. Sibling relationship quality was measured through parent and child report and coping strategies were measured via a child report measure. Sibling interaction quality was assessed through videotaped observations of dyadic interactions between the target sibling and the sibling affected with autism spectrum disorder. Analysis of variance was used to analyze obtained data. Results indicated that parent perceptions of sibling relationship quality improved following intervention and increases in positive sibling interaction during unstructured playtime were also found postintervention. Exploratory analyses also suggested positive effects on target siblings' knowledge of autism spectrum disorder as well as reduction in parent-reported internalizing symptoms in the target children. Results also suggested that response to this intervention program may be impacted to some degree by the sex and diagnostic status of the target child. Clinical implications and future research directions are discussed.