Epidermoid and dermoid cysts are benign lesions, which may occur anywhere on the body. Approximately 7% of these lesions occur in the head and neck region and 1.6% in the oral cavity. We present three cases of giant epidermoid cysts located on the floor of the mouth. Case 1 was a 22-year-old man referred to our clinic with a 10-year history of a submental mass, which began growing and causing pain in the throat. His physical examination revealed masses in both the submental and the sublingual regions. Magnetic resonance imaging (MRI) with contrast revealed a well-circumscribed isohypointense cystic mass with a ‘sack of marbles’ appearance. Case 2 involved a 23-year-old female referred to our clinic with difficulty in chewing and swallowing solid food for 1 week previously. Her physical examination revealed a sublingual mass displacing the tongue upward. Her MRI revealed a heterogeneous hyperintense cystic mass in the sublingual region. Case 3 was a 28-year-old man referred to our clinic with submental swelling, difficulty in breathing and swallowing, decreased tongue movements and snoring. His computerized tomography indicated a homogenous cystic mass in the submental region. The excision of the masses with an extraoral approach was performed in all the three cases. His histopathological examination revealed epidermoid cyst. In summary, epidermoid cysts may assume various appearances at radiological imaging.