Natural killer/T-cell lymphoma (NKTL) usually involves the nasal cavity or paranasal sinuses during the initial stage, and may invade the orbit or brain in the advanced phase. Thus, most patients with NKTL present with nasal symptoms. We report a case of NKTL that presented with ophthalmoplegia. MRI revealed pansinusitis and a mass lesion in the right maxillary sinus. An endoscopic biopsy revealed NKTL. NKTL should be included in the differential diagnosis of ophthalmoplegia.