Abstract Purpose Conservative approaches such as Schroth exercises and core stabilization exercises showed effective results in the treatment of idiopathic scoliosis. This study aimed to critically evaluate the magnitude effect of Schroth and core stabilization exercises using a systematic review and meta-analysis. Methods This study has been developed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement. The following three databases were searched for articles collection: Web of Science, PubMed, and Google Scholar. The key search terms were: Schroth exercise, core exercise, idiopathic scoliosis, Cobb angle, angle of trunk rotation, and quality of life. The articles included in our study was limited to original articles written only in English that met the following inclusion criteria: (1) Participants with idiopathic scoliosis; (2) Schroth exercises and core stabilization exercises used as interventions; (3) Cobb angle or angle of trunk rotation or quality of life used as outcome measures. Results Thirteen studies were included. Depending on the outcome measured, the magnitude effect of Schroth and core stabilization exercises ranged from small to almost large as follows: Cobb angle (SMD = – 0.376, p ˂ 0.001); angle of trunk rotation (SMD = – 0.268, p = 0.104); quality of life (SMD = 0.774, p = 0.002). By subgroup analysis, Schroth method showed a larger effect size than core stabilization exercises. Conclusion The current systematic review and meta-analysis indicates that both Schroth method and core stabilization exercises have a positive effect in subjects with idiopathic scoliosis. Subgroup analysis showed that the Schroth method had a larger effect size than the core stabilization exercises.