A 17-year old man developed acute onset blepharoptosis of the right upper eyelid with swelling. On examination, the patient exhibited right blepharoptosis without limitation of eye movement. MRI revealed swelling of right levator palpebral muscle. Oral steroid administration led to complete resolution of the blepharoptosis within 3 weeks. Isolated levator palpebral myositis is a rare disease, but, it is important for differential diagnosis on patients with blepharoptosis.