The purpose of this study is to examine the effect of couple sand play therapy on the sibling relationship between ADHD children and siblings. For this purpose, three pairs of ADHD children and siblings, who were recommended to participate in the study to improve their sibling relationships, A total of 12 weeks’ couple sand play therapy was performed every 50 minutes. In order to verify the effectiveness of couples sand play therapy, we conducted preliminary and post – hoc tests on the family system test and Sibling Relationship Questionnaire. The interactions were classified into positive and negative behaviors based on interaction observation scale. As a result, there was a statistically significant change in the pre – family perception of children with ADHD and siblings from ‘low’ and ‘middle’ to ‘middle’ and ‘high’ categories. In the process of the couple sand play therapy, the negative start behaviors of the siblings decreased but the positive start behaviors increased. In addition, as the session progressed, the negative elements of the sand tray decreased significantly and the positive elements gradually increased, and the confused boxes developed into an integrated tray. This study confirms that couples sand play therapy is effective in promoting communication and interaction between children with ADHD and siblings and improving sibling relationships.