In this study, we aimed to develop a countertransference scale based on the therapist-client relationship model in Sandplay Therapy. Additionally, we sought to validate the developed scale by examining its relationship with therapeutic alliance and the therapeutic relationship. Sandplay Therapy practitioners participated in data collection. The collected data were analyzed by calculating frequencies and percentages, conducting factor analysis, reliability testing, and correlation analysis. As a result, the countetransference scale comprised 30 items organized into five subfactors: ‘Mother-Child,’ ‘Power,’ ‘Scenery,’ ‘Shamanism,’ and ‘Wounded Healer.’ The validation of construct validity revealed significant positive correlations between the entire countertransference scale and the entire therapeutic alliance scale, as well as between the entire countertransference scale and the entire therapeutic relationship scale. The analysis revealed significant positive correlations between the overall reverse transfer scale and the alliance scale, as well as significant positive correlations between the overall reverse transfer scale and the therapeutic relationship scale.