Optic nerve sheath meningiomas are challenging lesions to manage. We report here a case of primary optic nerve sheath meningioma in a pregnant woman with sudden unilateral vision loss. Then we review the current literature on the subject, prognosis factors, and report the results of fractionated radiotherapy and current therapeutic guidelines. Pregnancy may accelerate growth of meningiomas and this diagnosis must be considered in all cases of optic neuropathy in pregnant woman.