Background Recently, randomized controlled trials (RCTs) have indicated that bariatric surgery in nonseverely obese patients with a body mass index (BMI) less than 35 kg/m(2) might be even superior to medical therapy with regard to type 2 diabetes mellitus (T2DM) remission, but the efficacy of laparoscopic Roux-en-Y gastric bypass (LRYGB) compared with laparoscopic sleeve gastrectomy (LSG) in nonseverely obese patients has not been conclusively determined. The objective of this study is to compare LRYGB versus LSG for T2DM in nonseverely obese patients. Methods A meta-analysis identifying RCTs evaluating LRYGB versus LSG for T2DM in nonseverely obese patients was conducted. The primary outcome was T2DM remission. Additional analyses comprised percent excess weight loss (%EWL), BMI, waist circumference, hemoglobin A1c (HbA1c), fasting plasma glucose (FPG), serum lipid level, medication use, quality of life, and adverse events. Results Four RCTs concerning total 296 patients were included. T2DM remission rate and %EWL were of no difference between the two bariatric procedures. LRYGB was associated with lower BMI, waist circumference, low-density lipoprotein, and higher high-density lipoprotein than LSG. However, HbA1c, FPG, total cholesterol, and triglyceride were not significantly different between the two surgical groups. The medication use and quality of life were improved in both two groups. The gastroesophageal reflux diseases of LRYGB group were less than that of LSG group. Dumping syndromes were noted more frequently in the LRYGB group. Conclusions Both LRYGB and LSG have comparative effect on resolving T2DM in nonseverely obese patients at midterm follow-up. Further RCTs should address the potential risks and long-term effects of LRYGB and LSG in nonseverely obese patients.