In the oral region, granular cell tumors often occur in the tongue, but rarely in the buccal mucosa. A case of granular cell tumor in the right buccal mucosa of a 74 year-old female is described. An elastic-hard solid mass about 1 cm in diameter was palpated under the right buccal mucosa. It was well-defined from the proximal tissues and adhered to part of the buccal mucosa. As a result of a biopsy, the diagnosis of a granular cell tumor was made. The tumor was resected together with the surrounding tissues under local anesthesia. Histopathological examination revealed large tumor cells with eosinophilic, PAS-positive fine granules under the hyperplastic epithelium. The granular cells stained negatively with PTAH, but positively with S-100 protein. Electron microscopic observations revealed a number of lysosomes of various sizes and densities within the cytoplasm of the tumor cells.