Osteosarcoma is a malignancy of mesenchymal cells, which have the ability to produce osteoid or immature bone. Osteosarcoma is the most common malignancy originating within bone, but occurs very infrequently in the jaws, comprising only 4% of the number of osteosarcomas of the long bones. Maxillary osteosarcoma presents with common clinical features of pain and swelling. Here we present a rare case of maxillary osteosarcoma in a 12-year-old girl. Diagnosis and preoperative assessment were performed using a combination of conventional radiography and advanced imaging. The aim of this case report is to draw attention to the possibility of diagnosing this tumor based on clinical and radiographic characteristics.