We examined a 15-year-old boy who had a ganglioglioma involving the left optic nerve, which caused proptosis, decreased vision, and optic atrophy. Computed tomography demonstrated an intraconal mass along the course of the orbital portion of the optic nerve. The only evidence of systemic neurofibromatosis was axillary freckling. The patient underwent a combined medial and lateral orbitotomy and excision of the tumor. Histologic examination demonstrated a mass composed of neurons and glial cells characteristic of ganglioglioma. After a one-year follow-up period, we have found no evidence of recurrence.