The diagnosis and management of third nerve dysfunction vary according to the age of the patient, the characteristics of the third nerve palsy, and the presence of associated symptoms and signs. Third nerve palsies can result from lesions located anywhere from the oculomotor nucleus to the termination of the third nerve in the extraocular muscles within the orbit, and may be the herald manifestation of underlying neurological emergencies such as intracranial aneurysm, pituitary apoplexy, and giant cell arteritis. Recent advances in noninvasive neuroimaging facilitate early diagnosis, but the management of a patient presenting with isolated third nerve palsy remains a challenge.