Pediatric mandible tumors are rare and generally benign but can be locally aggressive. Diagnosis and treatment involve tumor identification, excision, and subsequent reconstruction. Successful reconstruction should address form and function of the mandible while minimizing morbidity. The authors review the diagnosis and treatment of a benign pediatric mandible tumor and the use of nonvascularized rib graft for mandible reconstruction. The subject of interest is an 8-year-old boy who presented with progressive left-sided facial swelling and examination findings concerning for a mandibular neoplasm. A large bony tumor of the left mandibular ramus and condyle was identified on computed tomography scan. Needle aspiration was performed but was nondiagnostic. The patient underwent en bloc resection and immediate reconstruction utilizing nonvascularized rib graft. Pathologic analysis demonstrated a benign fibro-osseous lesion consistent with fibrous dysplasia, ossifying fibroma, or aneurysmal bone cyst. The patient had excellent recovery of jaw function and resumption of solid diet 5 weeks after reconstruction. Mandibular defects >6 cm in length often require free vascularized bone flaps for reconstruction; however, these procedures can have greater morbidity in the skeletally immature patient. Nonvascularized rib graft is a viable alternative that also allows for reconstruction of the mandibular condyle using the costocartilagenous cap of the harvested rib. The authors present this case as an example of a rare pediatric head and neck tumor and review of the approach to diagnosis and treatment, including special considerations for complex pediatric mandibular reconstruction.