The present invention provides a pharmaceutical composition for preventing or treating osteoarthritis comprising rebamipide as an active ingredient and a pharmaceutically acceptable carrier. The pharmaceutical composition may be for oral administration, for example an oral solid dosage form of a tablet or capsule form. The pharmaceutical composition may be formulated into a unit dosage form suitable for orally administering rebamipide in a dose ranging from 0.5 to 50 mg/kg, preferably from 0.6 to 6 mg/kg.