Dermoid cysts are uncommon, benign congenital lesions of ectodermal origin that can occur in any region of the body. They arise from epithelial rests during embryogenesis. Nearly 7% occur in the head-neck region, and they represent less than 0.01 % of all cavity cysts. They are usually diagnosed during the 2nd and 3rd decade of life, and rarely present in children. A case of dermoid cyst in the sublingual region in a 4-year-old female child was presented. The floor of the mouth is the most common location in the oral cavity and should be considered in the differential diagnosis of any midline lesion. Treatment is surgical excision.