Dermoid cysts are rare entity observed in oral cavity. In the head and neck region dermoid cyst is most commonly found at the lateral eye brow followed by floor of mouth. Histologically they can be categorized into epidermoid cyst, dermoid cyst and teratoma. Here we report a case of 28 years female who reported to us with a chief complaint of swelling in floor of mouth causing difficulty in swallowing and speech. Aspiration of swelling produced a keratin containing granular liquid. CECT was advised which showed a well-defined cystic lesion. Lesion was excised by extra oral submental incision under general anesthesia. Histologic examination showed dermoid cyst. After 4 months of follow up, there was no recurrence. Although this case could have been done intraorally we did it by submental incision to prevent the inadvertent iatrogenic injury to salivary gland ducts and other complications related to trans oral excision.