BACKGROUND: Bariatric surgery is the most effective option to reduce weight in morbid obesity patients. The techniques most employed are the restrictive surgery laparoscopic sleeve gastrectomy (LSG), surgical procedures of intestinal malabsorption, and both types (restrictive and intestinal malabsorption) such as the Roux-en-Y laparoscopic gastric bypass (RYLGB). AIMS: To determine if LSG is more effective than RYLGB for weight loss. METHODS: A systematic review and meta-analysis was carried out, including five clinical trials and sixteen cohorts comparing LSG versus RYLGB in weight loss and secondary outcomes: resolution of comorbidities, postoperative complications, operative time, hospital stay, and improvement in quality of life. RESULTS: Excess weight loss was 10.2% (mean difference [MD] 10.2; 95%CI -10.14; -9.90) higher in patients undergoing LSG than in patients submitted to RYLGB. Diabetes mellitus type 2 was resolved in 17% (relative risk [RR] 0.83; 95%CI 0.77–0.90) of cases, more significantly after LSG, arterial hypertension in 23% (RR 0.77; 95%CI 0.69–0.84), and dyslipidemia in 17% (RR 0.83; 95%CI 0.77–0.90). Postoperative complications were 73% higher in patients undergoing RYLGB (MD 0.73; 95%CI 0.63–0.83). The operative time was 35.76 minutes shorter in the LSG (MD -35.76; 95%CI -37.28; -34.24). Finally, the quality of life improved more in patients operated by LSG (MD 0.37; 95%CI -0.48; -0.26). CONCLUSIONS: The study demonstrated that LSG could be more effective than RYLGB in reducing the percentage of excess weight, comorbidities, postoperative complications, operative time, hospital stay, and in improving quality of life.