Five cases of "plunging ranula" are reported. In one case, treatment consisted of exteriorization and obturation by a removable, partial-denture-like splint. A second case was treated by total removal of both the ranula and the sublingual gland by a combined extraoral-intraoral approach. In the other three cases, treatment consisted of excision of the sublingual gland and marsupialization of the cyst by an intraoral approach. Since a plunging ranula is due to extravasation from the sublingual gland herniating through the mylohyoid muscle, excision of the sublingual gland followed by transoral drainage of the plunging ranula is regarded as the best treatment.