Plexiform neurofibromas in major salivary glands are rarely described. In the literature, most reported tumours have been present in the parotid gland region. A three-year-old boy with a family history of neurofibromatosis presented with a rapidly growing left submandibular mass. The clinical diagnosis was that of a neurofibroma rather than a primary salivary gland tumour. Resection of the lesion revealed a plexiform neurofibroma involving the submandibular gland. Although these tumours have a neurogenic rather than a salivary gland origin, they must be considered in the differential diagnosis of a salivary gland lesion in a patient with a history of neurofibromatosis.