In this study, to examine the effectiveness of the peer-relationship group art therapy program for children and adolescents, 45 papers published in Korea from 2001 to 2021 were selected and meta-analyzed. The study aimed to prepare a theoretical basis for the therapeutic intervention of peer-relationship group art therapy in children and adolescents by confirming the effect size through meta-analysis. For this purpose, the following results were obtained via conducting Comprehensive Meta-Analysis (CMA) 2.0. First, the overall effect size of peer-relationship group art therapy was Hedges’ g = 1.293, which showed a very large effect size. Second, due to examining the effect size according to the intervention-related components, the effect size was not significant for the subject's grade, subject type, study content, number of sessions, and session time; however, the smaller the group size, the larger and more significant the effect size. Therefore, this study verified the difference in the effect of a peer relationship group art therapy program for children and adolescents through meta-analysis. Based on the results, the implications of this study were then discussed.