Background: It remains unclear if Pilates is conducive to reducing spinal deformity and improving patients’ quality of life (QOL) with scoliosis. The aim of this study was to systematically review the published evidence to determine whether Pilates exercise training is an efficacious therapy for scoliosis. Methods: Searches was conducted in Medline, Embase, PubMed, Scopus, CINAHL, Physiotherapy Evidence Database (PEDro), Cochrane library, Baidu Scholar, and Green Medical to identify randomized studies that tested the effect of Pilates exercise training on Cobb angle, pain level, trunk range of motion (ROM), angle of trunk rotation, and QOL in idiopathic scoliosis. Separate meta-analyses were performed on the endpoints of these outcome measures. The PEDro scale was used to assess the methodological quality of the included studies. Results: This review included 10 randomized controlled trials (n = 359). PEDro scores ranged from 3 to 10, with the mean score across all articles being 5.3/10 and judged to be of fair quality. The results indicated that Pilates exercises was effective in reducing Cobb angle (standardized mean difference [SMD] = 1.23, 95% confidence interval [CI] = 0.11–2.35), angle of trunk rotation (SMD = 1.37, 95% CI = 1.01–1.73), and pain level (SMD = 2.78, 95% CI = 1.55–4.01), as well as improving trunk ROM (SMD = 1.23, 95% CI = 0.45–2.00), and QOL (SMD = 3.05, 95% CI = 2.59–3.51) in patients with scoliosis. Conclusion: Pilates exercise training may reduce the Cobb angle and trunk rotation, relieve pain, increase trunk ROM, and improve QOL for patients with scoliosis. Due to the poor quality of the evidence, however, these results should be interpreted with caution.