Crohn’s disease is a chronic inflammatory disease that involves the upper and lower gastrointestinal tracts, including the oral cavity. For the conventional treatment of inflammatory bowel diseases, steroids are usually used as induction therapy, and azathioprine is used as maintenance therapy. Steroids are associated with various side effects. Under rare circumstances, they can even cause psychotic symptoms, and reports on steroid-induced psychosis in the pediatric population are few. Here, we report the first case of steroid-induced psychosis in a 16-year-old female with Crohn’s disease administered with steroids as induction therapy in South Korea. She showed psychotic symptoms, including auditory hallucination, loosening of association, and idea of reference, after 2 weeks of administering prednisolone 60 mg/day. One week after steroid discontinuation, the patient gradually recovered and was treated with quetiapine. Therefore, pediatricians should be aware of serious psychiatric adverse effects when administering corticosteroids for various indications.