Whereas oral ranula is relatively common and presents as a cyst in the mouth, the plunging ranula is rare and manifests itself as a mass in the neck with or without an associated oral lesion. When there is a soft anterior neck swelling without oral swelling, diagnosis is still difficult. In such a case, clinical suspicion may be low and the pathologist may be misled by the histologic appearance. Recognition of the diagnosis of plunging ranula is essential for the correct treatment of these lesions. We report a case of a 4-year-old girl and review the literatures to discuss the differential diagnosis and treatment modalities.