We present a case of a 67-year-old man with chronic rhinosinusitis and a giant ossified sinonasal–orbital mass. Imaging revealed extensive involvement of the left maxillary sinus, orbit, and anterior skull base. A multidisciplinary team performed an expanded endoscopic endonasal transpterygoid–transmaxillary–transorbital approach with gross total resection. Reconstruction utilized a Resorb XG orbital implant, right nasoseptal flap, and left inferior turbinate flap. The patient was discharged on postoperative day two, with improvement in obstruction and diplopia recovery.