Stevens-Johnson syndrome (SJS) presents with widespread blisters, erythematous or purpuric macules, and one or more mucous membrane erosions. Various etiologic factors, including infection, vaccination, drug administration, systemic diseases, physical agents, and food have been implicated as causes of SJS. Mycoplasma pneumoniae is the most common infectious agent to cause SJS in children. In recent literature, M. pneumoniae -induced SJS with mucositis that lacks the typical target lesions has been described. We report a case of a 6-year-old boy with swelling, peeling of the lips, and red eyes with photosensitivity. On physical examination, he showed severe oral mucositis and conjunctivitis with no evidence of skin lesions. Mycoplasma antibody, which was positive with titers of more than 1:2,560. For patients presenting with fever and mucositis of unknown origin, M. pneumoniae should be considered.