Background: One anastomosis gastric bypass (OAGB) and sleeve gastrectomy (SG) are popular bariatric surgeries for morbid obesity. Reports on the safety and effectiveness of SG and OAGB are inconsistent. This meta-analysis investigated the clinical outcomes of SG versus those of OAGB for morbid obesity. Methods: Based on PRISMA guidelines, we searched the published articles in English from Scopus, PubMed (Medline), Central (Cochrane), and Embase databases. Articles were retrieved from the start date of each database to February 13, 2019. Statistical analysis of this meta-analysis was conducted in Stata 14.0, and the most appropriate effect model was chosen based on heterogeneity. Results: A total of 20 articles examining 4064 OAGB patients and 3733 SG patients were included in this meta-analysis. Compared with SG, OAGB showed a higher percentage excess weight loss (%EWL) at 6 months (weighted mean difference (WMD) = 11.32; 95% CI 6.00–16.64), 12 months (WMD = 8.22; 95% CI 3.78–12.66), 24 months (WMD = 10.19; 95% CI 0.88–21.25), 36 months (WMD = 7.93; 95% CI 3.37–12.48), 48 months (WMD = 17.22; 95% CI 7.37–27.06), and 60 months (WMD = 16.43; 95% CI 8.96–23.90). In addition, OAGB was associated with a lower rate of postoperative leak, gastroesophageal reflux disease, revisions, mortality, and dyslipidemia remission rates. However, OAGB increased the incidence of ulcers, malnutrition, and bile reflux. Conclusion: OAGB is more effective for %EWL and dyslipidemia remission than SG. In addition, OAGB may lower the risk of postoperative leak, gastroesophageal reflux disease, revision, and mortality. Further comparisons of the clinical outcomes of OAGB versus SG for morbid obesity would benefit from more high-quality controlled studies. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.