Despite the psychosocial difficulties common among young adults with autism spectrum disorders (ASD), little to no evidence-based social skills interventions exist for this population. Using a randomized controlled trial (RCT) design, the current study tested the effectiveness of an evidence-based, caregiver-assisted social skills intervention known as "PEERS for Young Adults" with high-functioning young adults with ASD (ages 18-23) using self- and caregiver-report measures. Results revealed that treated young adults reported significantly less loneliness and improved social skills knowledge, while caregivers reported significant improvements in young adults' overall social skills, social responsiveness, empathy, and frequency of get-togethers. Results support the effectiveness of using this caregiver-assisted, manualized intervention for young adults with ASD.