Plasmacytoma is a neoplastic proliferation of monoclonal plasma cells, which can present clinically as solitary bone neoplasm, extramedullary plasmacytoma, and multiple myeloma. The biological behavior of these tumors is variable from periods of clinical latency to rapid growth and progression from localized forms to more disseminated multiple myeloma. We present the case of solitary plasmacytoma of the mandible with rare bilateral involvement in a 65-year-old female patient. This paper highlights the importance of understanding the maxillofacial manifestations of the disease by the dentist for early diagnosis and thus better prognosis.