Background and aim: the present study was conducted with the aim of evaluating the long-term hard tissue stability and relapse factors following surgical-orthodontic treatment. Method: Databases of PubMed, Scopus, Web of Science, EBSCO, ISI Web of knowledge and Embase were searched for systematic literature until July 2022.  95% confidence interval for mean differences with fixed effect model and Inverse-variance method were calculated. To deal with potential heterogeneity, random effects were used and I2 showed heterogeneity. Meta-analysis was performed using Stata/MP v.17 software. Result: In the initial review, duplicate studies were eliminated and abstracts of 201 studies were reviewed, the full text of 38 studies was reviewed by two authors, finally, ten studies were selected. Overbite changes, Upper incisor changes and Lower incisor changes after combined orthodontic and orthognathic surgical treatment in class II and III patients during long-term follow-up was 1.80 (MD 95% CI; 1.43 and 2.17), -0.51 (MD 95% CI; -1.08 and 0.05) and 0.27 (MD 95% CI; 1.03 and 1.58), respectively. Conclusion: Based on the findings of the present study, in patients with skeletal class II and III, the results of long-term dental changes after combined orthodontic and orthognathic surgery are very diverse.