Cerebral palsy normally showed impairment of movement and postural control, thus, a standard or specific tool for evaluating the postural control problem is an important issue in planning suitable treatment for patients. This study aims to translate the Kids Balance Evaluation System Test (Kids-BESTest) from the original version to the Thai version (Kids-BESTest-Th) and study the reliability of the Kids-BESTest-Th in cerebral palsy patients. The translation processes in this study were forward and backward translation. The Kids-BESTest was translated by a professional English linguist and physical therapist. Subsequently, the content validity ratio (CVR) was measured in the Kids-BESTest-Th by the physical therapists and lecturers who have expertise in children with cerebral palsy. After that, two physical therapists had applied the Kids-BESTest-Th to evaluate the balance systems in ten children with cerebral palsy. The Balance system was measured at 2 periods a week apart. Statistical analysis was the intraclass correlation coefficient (ICC) for calculating the inter- and intra-rater reliability. The study showed excellent inter - and intra-rater reliability (ICC > 0.94) of The Kids-BESTest-Th in both total and section scores. To conclude, the Kids-BESTest-Th showed excellent reliability, which can apply to evaluating the balance systems in cerebral palsy. The concurrent validity of the Kids-BESTest-Th would be a suggestion for further study.