We report a child presenting with intermittent ophthalmoplegia and fluctuating ptosis and facial weakness whose evaluation revealed no evidence of myasthenia gravis but did reveal hyperthyroidism secondary to Graves disease. Successful treatment of the child’s endocrinopathy resulted in complete resolution of his presenting symptoms. Children presenting with ophthalmoplegia and ptosis without proptosis should be evaluated for hyperthyroidism if no evidence of a myopathy or disorder of neuromuscular junction transmission is found.