Eighty adolescents with AIS (Cobb angle 10–45°) were randomized into two groups: a Schroth exercise and brace group (n=40) or a brace-only group (n=40). The primary outcomes were scoliosis severity (Cobb angle and ATR) and quality of life (SRS-22 score). Secondary outcomes included the sum of curvatures. Measurements were conducted at baseline, 12 months, and 6 months post-intervention (18 months). Overall, the Schroth exercise group showed statistically significant improvements in Cobb angle, ATR, and SRS-22 score at 12 months compared to the brace-only group. Improvements in ATR and SRS-22 were sustained at 18 months. This suggests that supervised long-term Schroth exercises improve scoliosis severity and quality of life more effectively than brace-only treatment.