Few studies have investigated the effect of age on treatment effectiveness of evidence-based social skills training in autism spectrum disorder (ASD) adolescents. This study evaluated the effectiveness of Program for the Education and Enrichment of Relational Skills (PEERS®) in different ages of ASD adolescents. A total of 110 ASD adolescents aged 11–19 years were divided into early, middle, and late adolescence groups, and the changes in outcome measures following intervention were compared among the three groups. We found that the improvements in social competence after PEERS® were significant, but the treatment effects were not significantly different among the three age groups. The findings suggest that PEERS® is beneficial for ASD adolescents regardless of patient age and adolescence stage.
