Leiomyoma is benign tumour arising from smooth muscle that occurs between 40 and 49 years of age. Leiomyomas are a rare entity in the oral cavity and if present they are usually localized on tongue, lips and palate. Leiomyoma appears to be well-defined mass, with slow growth. The treatment is surgical excision. We report a 10-year girl child, with a lump in the right retromolar trigone region intraorally. Excisional biopsy performed under general anaesthesia revealed the specimen to be a leiomyoma. The low incidence of this pathology, the age of the patient and the location are unusual.