Waist line asymmetry is a major cosmetic concern in patients with adolescent idiopathic scoliosis (AIS). The primary surgical goal in patients with AIS is to correct spinal deformities and prevent further progression while maintaining global alignment. Additionally, an important objective of surgical treatment is to address physical appearance by reducing asymmetry. This study aimed to evaluate changes in waistline asymmetry using digital photographs in adolescents with thoracolumbar/lumbar (TL/L) scoliosis who underwent corrective surgery. We retrospectively analyzed the data of patients with Lenke types 5C and 6C AIS who underwent posterior fusion surgery with at least 2years of follow-up. Waist line asymmetry was assessed using digital photography. The waist angle ratio (WAR), waist height angle (WHA), and waistline depth ratio (WLDR) were measured pre- and postoperatively. Radiographic parameters and the revised 22-item Scoliosis Research Society Questionnaire (SRS-22r) were also evaluated. Forty-two patients (40 females and 2 males; 34 with type 5C and 8 with type 6C) were included in the study. The WAR, WHA, and WLDR significantly improved after surgery (0.873 → 0.977, - 2.0° → 1.4°, and 0.321 → 0.899, respectively). Every waistline parameter moderately correlated with the apical vertebral translation of the TL/L curve (WAR: r = - 0.398, WHA: r = - 0.442, and WLDR: r = - 0.692), whereas no correlations were observed with the TL/L curve magnitude. No correlations were observed between the photographic parameters and SRS-22r scores. Lateral displacement of the apical vertebra on the TL/L curve correlated with waistline asymmetry. Preoperative waistline asymmetry improved with scoliosis correction. Level 4.