This study is aims to calculate the effect size of group art therapy on reducing depression and anxiety for children and adolescents. A meta-analysis was conducted, analyzing 33 papers published in Korea between 2000 and December 2022, which focused on depression and anxiety as dependent variables, children and adolescents as participants, and group art therapy as the intervention method in thesis and academic journals. The random-effects model was applied to calculate the average effect size of individual studies, and meta-ANOVA was performed to examine the moderating effects of specific variables. Additionally, Funnel Plots were utilized to verify publication bias in the collected papers. The findings are as follows: First, the overall effect size (ES) for group art therapy program targeting depression and anxiety was 1.65, indicating a high effect size. Second, for the dependent variable, the effect size (ES) for depression was 1.77, and for anxiety, it was 1.50, both showing high effect sizes, with no significant difference between the two dependent variable (Q=0.56, p=0.45). Third, the effect size of moderating variable were significant based on age, target type, number of participants, number of sessions per week, and duration of each session. Based on these research results, the significance and limitations of this study were discussed.