Background: Fibromatosis is a group of benign tumors originating from connective tissues of muscle, overlying fascia, periosteum, or aponeurosis. However, they might need several excisional resections, owing to compressive effects on adjacent vital structures. Case Report: Here, we discussed a case of submandibular fibromatosis in a 3-year-old girl. She underwent a conservative surgical procedure without a wide mandible bone resection. She received no adjuvant therapy. The postoperative period was uneventful with an appropriate cosmetic and functional outcome. A 1-year follow-up revealed no recurrence. Conclusion: Fibromatosis of the head and neck in children is a rare condition, which needs a multidisciplinary agreement for its appropriate management. A complete surgical removal often leads to a proper outcome. Adjuvant therapy should also be kept in mind for recurrent lesions not candidate for surgical removal or in case of remnant tumors.