Fibromatosis comprises a broad group of benign fibrous tissue proliferations having similar microscopic picture and whose biologic behavior lies between that of benign fibrous lesions and fibrosarcoma. It is characterized by infiltrative growth and a tendency toward recurrence; however, these lesions never metastasize. Fibromatosis are classified as superficial and deep. Superficial are slow growing and of small size. The deep type is aggressive, grows quickly, involves deep structures and penetrates extensively mimicking malignancy. Head and neck lesions are considered as deep fibromatosis and often called as juvenile aggressive fibromatosis. Pertaining to the high recurrence rate wide surgical excision is the favored choice of management. Here, we report a case of Juvenile aggressive fibromatosis of the oral cavity in a 10 year old boy involving right side of the mandible affecting the eruption and normal positioning of the permanent tooth bud. Lesion was operated with conservative surgical approach. Two years follow up exhibited positive outcome without any local recurrence.