Radiation-induced oral mucositis is an oral mucosal injury caused by radiation ionizing radiation, which often manifests as oral mucosal congestion, erosion, and ulcers. Radiation-induced oral mucositis manifesting as vascular proliferative changes in the oral mucosa has not been reported. We report a case of oral mucosal atypical vascular proliferation after radiotherapy for a malignant maxillofacial tumor. We discussed the mechanism and treatment of aty-pical vascular proliferation in the oral mucosa secondary to radiotherapy, including diagnosis, treatment, and previous literature.