This study aimed to evaluate the validity and reliability of the newly adapted Korean version of the Bad Sobernheim Stress Questionnaire-Brace (K-BSSQ-Brace). The original German BSSQ-Brace was translated, back-translated, and underwent a comprehensive cross-cultural adaptation process. The K-BSSQ-Brace and the previously validated Korean version of the Scoliosis Research Society-22 Outcomes Questionnaire (K-SRS-22) were then administered to 120 adolescents with idiopathic scoliosis (AIS). Reliability was assessed using kappa statistics for item agreement, the intraclass correlation coefficient (ICC), and Cronbach's α for internal consistency. The K-BSSQ-Brace demonstrated strong reliability, with all items showing kappa values above 0.6 and an excellent test-retest ICC of 0.921. Internal consistency was high, with a Cronbach's α of 0.882. Convergent validity was confirmed through a moderate correlation between the K-BSSQ-Brace and K-SRS-22. Discriminant validity was supported by a significant association between K-BSSQ-Brace scores and major curve magnitude. These findings suggest that the K-BSSQ-Brace is a reliable and valid tool for assessing the quality of life in Korean AIS patients undergoing brace treatment.