To determine the midterm outcome of lateral thoracotomy (LT) in skeletally immature patients concerning thoracogenic scoliosis development and lung parenchyma resection (LPR) extent. In total, 129 children met the inclusion criteria: (1) LT during the study period; (2) skeletally immature at the time of LT; (3) clinical and radiographic follow-up of at least 3years; and (4) no spinal or thoracic deformity on radiographs before LT. Patients were grouped according to their underlying disease, age at LT, and LPR extent. Radiographic parameters were assessed. Kaplan-Meier survival curves and univariate and multivariate analysis were performed. Of 129, 108 patients underwent pneumonectomy (9; 9.1%), lobectomy (79; 61.2%), segmentectomy (20; 15.5%) and 21 patients LT without LPR. The mean age at LT and at last radiological follow-up was 5.5years (birth-17.8) and 15.2years (3.4-33.2). The mean follow-up was 10years (3-28.1). Scoliosis developed on average 5.3years after LT. The mean Cobb angle was 22.1° (11-90°); > 10° in 37/129 patients (28.7%), of whom 5/129 (3.9%) had > 45°. The average vertebral rotation was 16.2° (2-43°; grade 0-II). RVAD was 26.5° (8°-33°) and 15.3° (2-43°) in patients with Cobb > 45° and ≤ 45°. Gender, age at surgery, and extent of LPR were not risk factors for post-thoracotomy scoliosis (p > 0.05), although younger patients developed a more severe deformity. Although post-thoracotomy scoliosis is not associated with significant rotation, the risk of curve progression > 45° is relatively high. Regular follow-up is required as scoliosis may develop several years after LT with or without LPR.