Art therapy has often been applied in the treatment of traumatized adults, and good results in clinical practice have been reported. However, although art therapy experts underline these benefits, the effectiveness of art therapy in trauma treatment has not been established by systematic review. The aim of this systematic review is to identify and evaluate empirical evidence of the effectiveness of art therapy for trauma treatment. As a result of the systematic review, six controlled, comparative studies on art therapy for trauma in adult patients were found. In half of the included studies, a significant decrease in psychological trauma symptoms was found in the treatment groups, and one study reported a significant decrease in depression. Although there are limitations in the number of included studies, the number of participants, the heterogeneity of included studies, and their methodological quality, the results contribute to insight into the effectiveness of art therapy in trauma treatment and form an evidence base for the urgent need for further research on art therapy and trauma treatment.