Summary We encountered a case of childhood-onset lymphocytic infundibuloneurohypophysitis, based on the MRI and endocrinological findings, with decreased function of the anterior and posterior lobes of the pituitary. Three years after the diagnosis, the patient developed non-alcoholic steatohepatitis (NASH), which was effectively treated by growth hormone (GH) supplementation. The present case demonstrated that NASH can be effectively treated by short-term GH supplementation, even in late childhood. Learning points In recent years, the efficacy of growth hormone replacement therapy in normalizing the liver function of adult-onset growth hormone deficiency patients with non-alcoholic steatohepatitis (NASH) has been reported. Lymphocytic infundibuloneurohypophysitis is a very rare disease, particularly in childhood. We here presented a rare case of a child with lymphocytic infundibuloneurohypophysitis who developed NASH and showed substantial improvement in liver function after growth hormone treatment.