Metabolic and bariatric surgery (MBS) is an effective treatment for patients with morbid obesity and its comorbidities. However, many patients experience weight regain (WR) after achieving their nadir weight. Establishing the definition of WR is challenging as postoperative WR has various definitions. Risk factors for WR after MBS include anatomical, racial, hormonal, metabolic, behavioral, and psychological factors, and evaluating such factors preoperatively is necessary. Long-term regular follow-up and timely treatment by a multidisciplinary team are important because WR after surgery is multi-factorial. Although lifestyle interventions that focus on appropriate dietary education, physical activity education or interventions, and behavioral psychological interventions are suggested, more well-designed studies are needed because studies evaluating intervention methods and the effectiveness of WR prevention are lacking. Anti-obesity drugs can be used to prevent and manage patients with WR after MBS; however, more research is needed to determine the timing, duration, and type of anti-obesity drugs used to prevent WR.