This study used a randomized controlled trial to compare two distinct models of group social skills interventions with adolescents with autism spectrum disorder (ASD). Participants had a confirmed diagnosis of ASD, an IQ greater than or equal to 70, and were educated in the general education setting. Data from 62 adolescent participants who were randomized to one of two treatment conditions (SKILLS vs. ENGAGE) were analyzed. SKILLS participants had a diagnosis of ASD, or social difficulties. ENGAGE groups included adolescents with ASD and typically developing (TD) peer mentors. SKILLS and ENGAGE participants both improved joint engagement and reduced solitary engagement, however, SKILLS participants reported higher social stress and lower quality interpersonal relationships at exit, and increased emotional symptoms and problem behaviors at follow-up compared to the ENGAGE group. The findings suggest that within inclusive secondary school settings, it may be beneficial to include TD peers in social intervention groups.