Dermoid cysts are rare developmental benign lesions that arise as a result of ectodermal differentiation of multipotent cells. Histologically the cysts are classified as dermoid, epidermoid and teratoid cysts depending on the presence of adnexal structures and derivatives of germ layers. When dermoid cysts appear in the floor of the mouth they can cause difficulty in deglutition and respiration. The differential diagnosis of dermoid cyst could be infection, ranulaor tumor. Intraoral or extra oral approach for enucleation is the method of treatment. Dermoid cysts have a good prognosis with low malignancy and recurrence rate. A case report of a dermoid cyst in the floor of the mouth is presented in this paper along with clinical, histopathological evaluation and the treatment.