Malignant peripheral nerve sheath tumor (MPNST) of the mandible is an uncommon tumor that develops either from a preexisting neurofibroma or de novo. MPNSTs are sarcomas that originate from peripheral nerves or from cells associated with the nerve sheath, such as Schwann cells, perineural cells or from fibroblasts. Because MPNSTs can arise from multiple cell types, the overall appearance can vary greatly from one case to the next. A case of MPNST of the right side of the mandible in a 23-year-old female is reported.