Problem Statement: "Self-concept" is a primary issue of emotional and social development. Though the most important stage in the formation of self-concept is childhood, measuring the development of the self in the preschool period is quite difficult, for the tools used to measure children's self-concept either require the child's knowing how to read and write or have been designed to measure the self-concepts of children with special developmental characteristics. Purpose of Study: This study aimed to adapt the DeMoulin Self-Concept Developmental Scale (DSCDS) for 5-and 6-year-old Turkish children and to determine its validity and reliability for determining the self-perception of these children with normal development. Methods: The study was conducted with 345 participants, roughly half of whom were Turkish children aged 5-6 years. The scale was investigated for its linguistic equivalence and applicability. Data was collected by using both the original DSCDS translated into Turkish and the Marmara Social-Emotional Adjustment Scale and the Marmara Readiness for School Scale. Ultimately, the validity and reliability of the Turkish DSCDS were analyzed. Findings and Results: The maximum reliability produced according to Cronbach's alpha and Spearman's rank correlation coefficient was 0.88, and the lowest reliability calculated with the Guttman method was 0.88. It was determined that the DSCDS for these children composed of 29 items and two subdimensions applied to participants according to the Turkish Developmental Norms as a high-quality measurement tool. Conclusions and Recommendations: With the validity and reliability studies of the DSCDS for children aged 5-6 years completed, a norm study can be arranged in order to expand the scale by applying it to groups of children with different characteristics, such as those with a low socioeconomic status, those residing in orphanages, and adopted children.