Osteomas are rare, slow-growing, benign bone tumors that preferentially develop in the paranasal sinuses. We report a case of a giant osteoma of the left maxillary sinus in a 29-year-old man which was diagnosed by imaging and endoscopy and treated surgically because of the patient's symptoms and maxillary sinus distortion. Given the large volume and location of the osteoma, resection was performed through an external sublabial approach, according to the Rouge-Denker technique. There were no postoperative complications. There was no sign of recurrence at 5 years follow-up. A review of the literature for maxillary sinus osteomas was performed. Indications for surgery and the different surgical approaches available are discussed.