Hashimoto's encephalopathy is a steroid-responsive, relapsing or progressive encephalopathy associated with thyroid autoantibodies. Age at presentation varies from 10 to 78 years. In children, Hashimoto's encephalopathy is rare, and seizures, confusion and hallucinations are the most commonly described features. We report a 10-year-old girl with the diagnosis of Hashimoto's encephalopathy and review the literature.