Duodenal diverticulum is a common gastrointestinal lesion, but its complications are uncommon. Perforation of duodenal diverticulum following laparoscopic sleeve gastrectomy (LSG) is extremely rare and poses significant diagnostic and therapeutic challenges. This article reports a relevant case treated at Chu Hsien-I Memorial Hospital of Tianjin Medical University with favorable outcomes. The occurrence of duodenal diverticulum perforation after LSG may be associated with increased intraduodenal pressure caused by accelerated gastric emptying postoperatively and dietary factors. The treatment of such patients should be individualized based on the location of perforation, extent of infection, and general condition of the patient; in this case, percutaneous puncture and drainage achieved excellent results. Given that duodenal diverticulum may affect surgical implementation and postoperative prognosis, it is recommended that routine gastroduodenoscopy and abdominal computed tomography (CT) be performed before LSG to evaluate the diverticulum and optimize surgical decision-making. Whether gastric bypass surgery is a superior option for obese patients with concurrent duodenal diverticulum who require metabolic bariatric surgery remains a question worthy of further exploration.