Purpose: To report a rare case of severe ocular hypertension following intravenous methylprednisolone treatment in a child with bilateral optic neuritis.Case summary: A 6-year-old girl presented with bilateral severe visual loss and disc swelling. Magnetic resonance imaging revealed optic nerve enhancement, and she received high-dose intravenous methylprednisolone for 3 days and oral prednisolone 30 mg/day for 2 weeks. Two weeks after initiating treatment, ophthalmologic examination revealed an intraocular pressure (IOP) of 46 mmHg in the right eye and 42 mmHg in the left eye. The best-corrected visual acuity was 1.0 in the right eye and 0.6 in the left eye. Relative afferent pupillary defect was noted in the left eye. Fundus examination showed normal cup-to-disc ratio (0.4) in both eyes. The iridocorneal angle was open in all directions. The treatment plan included the cessation of oral prednisolone and initiation of latanoprost and dorzolamide-timolol fixed combination agent. After 12 hours, the IOP decreased to 18 mmHg in the right eye and 14 mmHg in the left eye. Six months later, her visual acuity was 1.0 in both eyes, and IOP was maintained at 11 and 13 mmHg in the right and left eye, respectively. Optic disc examination showed no sign of glaucomatous change with normal cup-to disc ratio in both eyes.Conclusions: Since steroid medication may cause asymptomatic IOP elevation, regular intraocular pressure measurements are required during steroid treatment for pediatric optic neuritis. The administration of IOP-lowering eyedrops returned IOP to the normal range without damaging the optic nerve.