Raising a child with an Autism Spectrum Disorder (ASD) is associated with increased family chaos and parent distress. Successful long-term treatment outcomes are dependent on healthy systemic functioning, but the family impact of treatment is rarely evaluated. The Program for the Education and Enrichment of Relational Skills (PEERS) is a social skills intervention designed for adolescents with high-functioning ASD. This study assessed the impact of PEERS on family chaos, parenting stress, and parenting self-efficacy via a randomized, controlled trial. Results suggested beneficial effects for the experimental group in the domain of family chaos compared to the waitlist control, while parents in the PEERS experimental group also demonstrated increased parenting self-efficacy. These findings highlight adjunctive family system benefits of PEERS intervention and suggest the need for overall better understanding of parent and family outcomes of ASD interventions.