Marginal ulcer (MU) is a potential complication following Roux-en-Y gastric bypass (RYGB), with a mean prevalence of 4.6%. Early identification and prompt intervention are crucial to mitigating further complications. The pathophysiology of MU is complex and involves multiple factors, including smoking,Helicobacter pyloriinfection, non-steroidal anti-inflammatory drug (NSAID) use, and larger pouch size. Patients with MU may experience acute or chronic abdominal pain. Rarely, they may present with a complication from the ulceration, such as bleeding, perforation, or strictures. Following diagnosis by endoscopy, management of MU typically involves modification of risk factors and medical therapy focused on proton pump inhibitors. In case of complicated ulcers, surgical intervention is often required for the repair of the perforation or resection of the stricture. For recurrent or recalcitrant ulcers, endoscopic coverage of the ulcer bed, resection of the anastomosis, and abdominal or thoracoscopic truncal vagotomy may be considered. This review aims at providing an overview of the etiology, diagnosis, and management of MU after RYGB.