An instance of sebaceous carcinoma that presented as a mass in the left buccal mucosa is described. This is the first known report in the English-language literature of a sebaceous carcinoma presenting as an intraoral tumor. The light and electron microscopic findings are described. The histologic differential diagnosis, clinical behavior, and appropriate therapy are discussed. Previously reported intraoral sebaceous neoplasms and sebaceous carcinomas of the parotid are reviewed.