Dermoid and epidermoid cysts in the oral cavity frequently develop in the midline or sublingual region of the floor of the mouth. Here, we report a rare case of an epidermoid cyst in the submandibular region. The patient was a 69-year-old man with a chief complaint of a mass in the right submandibular region. A mobile, elastic, relatively soft mass without tenderness was palpable in this region. The skin covering the mass was normal. MRI showed a cystic lesion measuring 3.5 × 3.0 cm under the platysma in the right submandibular region. Cystectomy was performed under general anesthesia. There was no adhesion to surrounding tissue and the right submandibular gland was preserved. The surgical specimen was cystic and contained soybean cord-like materials. Histopathologically, the cyst wall was lined by stratified squamous epithelium with no skin appendage, suggesting an epidermoid cyst. The postoperative course was uneventful and without recurrence after 28 months.