In this study, the effectiveness of art therapy for children with developmental disabilities was examined through a meta-analysis of single subject studies conducted in Korea. A total of 17 papers were selected by collecting studies published in Korea between 2000 and 2021, based on recommendations for evaluating single-subject research quality (Logan et al., 2008). The inter-rater reliability was 88.4%, and the analysis frame was confirmed through revision. The percentage of non-overlapping data was used to calculate the effect size. As a result, the overall effect size was 81.2%, indicating a fairly high level. Art therapy intervention for children with autism spectrum disorder showed a high effect size (88.6%) and media-centered art therapy showed a very high effect size (91.1%). Additionally, the effect size was higher for interventions targeting problem behavior compared to that targeting emotional or social change. Based on these results, the implications and limitations of this study are discussed.