This study provided a systematic review and meta-analysis of UCLA PEERS® for social skills improvement in adolescents or young adults with autism. A total of 21 randomized controlled trials and 10 non-randomized controlled trials were included, and six different outcome indicators were analyzed. The results showed that PEERS improved participants' knowledge of social skills, ability to apply social skills, and emotional intelligence, and the difference between caregiver-reported scores and teacher-reported scores was statistically significant. The PEERS intervention produced the smallest effect using PEERS in East Asia. This study discussed the significance of PEERS on the improvement of social skills in ASD and the reasons for the results of the subgroup analyses, and provided some recommendations for PEERS intervention methods that may help to improve the effectiveness of the intervention.