Pleomorphic adenoma is the most common type of benign salivary gland tumor. It can also be found in the larynx, ear, neck, and nasal septum. It is rarely found in the maxillary sinus, and it has never been reported in the frontal sinus. We report a case of pleomorphic adenoma of the frontal sinus that masqueraded as a mucocele. We discuss the clinical presentation, diagnosis, and treatment of this patient, and we review the literature.