Purpose: The Program for the Education and Enrichment of Relational Skills (PEERS®) is a group-based social skills training program for adolescents on the autism spectrum. Although the program has been shown to be effective in improving social skills in autistic adolescents, evidence of its effectiveness from the Mandarin-speaking Chinese population is sparse. The present study used a non-randomized, pre- and post-intervention research design to investigate the feasibility and cultural validity of the program, as well as examine the moderators of intervention outcomes. Methods: Thirty-three autistic adolescents with intelligence quotient above 70 (M[subscript age] = 13.57, SD[subscript age] = 1.43; Male: Female 25:8) and their parents received 14 concurrent 90-minute sessions. Adolescents' autistic traits, challenging behaviors, emotional functioning, socio-cognitive process, social environment factors (school support), and caregivers' well-being were evaluated. Results: The findings suggest that with minor adjustments, the Mandarin version of PEERS® was generally acceptable and feasible for autistic adolescents and their parents. PEERS® may improve the social skills knowledge, reciprocal communication abilities, and emotional well-being of autistic adolescents. Also, participants with a higher level of school support, and parents with lower perceived subjective well-being at baseline may gain more benefits from PEERS®. The cultural adaptation and acceptability of the Mandarin Version of PEERS® were discussed. Conclusion: This feasibility study (Chinese Clinical Trial Registry: ChiCTR2200061417, 2022-06-23, retrospectively registered) provides a basis for further randomized control trials of the Mandarin version of PEERS®.