Esophageal leiomyoma is a rare disease commonly reported in middle-aged patients with a male predominance. Many patients are asymptomatic, and a few may present with symptoms such as dysphagia and chest pain. However, heartburn is only reported in patients with accompanying hiatal hernia. We hereby report a giant lower esophageal leiomyoma with concomitant hiatal hernia in a young Vietnamese female, who presented with refractory gastroesophageal reflux symptoms. The diagnosis was challenging as the tumor grew outward. As a consequence, the patient did not experience dysphagia and the tumor was hardly detected under endoscopy. The hiatal hernia in this patient was probably related to the presence of the leiomyoma. It is important to look carefully for submucosal tumor at the lower esophagus and cardia under endoscopy in patients with similar manifestations.