The sebaceous nevus syndrome describes the rare association of a sebaceous nevus with systemic features such as mental retardation, seizures and colobomas (among others). It is thought to be a cutaneous mosaic inherited as a paradominant trait. Three cases are provided illustrating the intraoral manifestations of the syndrome. The first histological comparison of contiguous mucosal and cutaneous lesions is provided. We also describe the possible association of SFM syndrome with a benign fibrous histiocytic lesion of the mandible. This and other mandibular tumors associated with the sebaceous nevus syndrome may have significant implications for patients. Awareness of the potential presence or development of significant intraoral lesions in association with the sebaceous nevus syndrome is important for those involved in the care of patients with this syndrome.