A 72-year-old man was referred to the Service of Ophthalmology due to a 2-year history of ptosis and a painless mass in the lateral orbital margin of the right eye. Orbital MRI revealed a well-demarcated lesion in the superotemporal quadrant of the orbit. After surgical excision, histopathological examination led to the diagnosis of nerve sheath myxoma, a tumor composed of myxoid nodules separated by fibrous septa with spindle-shaped and stellate cells. Many of these cells were immunostained with antibodies to S-100 protein. This is the first case reported in the literature of such a tumor located in the orbit, and, though extremely rare, it should be considered in the differential diagnosis of orbital tumors.