High rates of revision surgery have been reported for laparoscopic sleeve gastrectomy (LSG), with weight regain (WR) as the most frequently reported cause. Roux-en-Y gastric bypass (RYGB) is the most commonly performed revision procedure, whereas one-anastomosis gastric bypass (OAGB) is a less popular approach. A single-blinded randomized controlled trial was conducted. One hundred seventy-six patients were enrolled and randomized. After loss to follow-up, 80 patients for RYGB and 80 patients for OAGB were analyzed, with a 2-year follow-up. Patients with grade B or higher gastroesophageal reflux disease (GERD) were excluded. Early and late postoperative complications were recorded. Body mass index (BMI), percentage of excess BMI loss (%EBMIL), nutritional laboratory test results, and the resolution of associated medical problems were assessed after revision surgery. After 2 years, both groups achieved significantly lower BMI than their post-LSG nadir BMI (p < 0.001). The %EBMIL changes showed significantly faster weight loss in the OAGB group than in the RYGB at the 6-month follow-up (mean difference: 8.5%, 95% confidence interval [CI]: 0.2 to 16.9%). However, at 1-year and 2-year follow-ups, the differences were statistically insignificant (p > 0.05). Early and late complications were similar between two groups. Both groups showed improvement or resolution of associated medical problems, with no statistically significant differences after 2 years (p = 1.00). Both revisional RYGB and OAGB have comparable significant weight loss effects when performed for WR after LSG. After a 2-year follow-up, both procedures were safe, with no significant differences in the occurrence of complications and nutritional deficits.