The objective of this chapter is to introduce the autoimmune hepatitis. Autoimmune disorders are mostly seen in female of 15–40 years of age and are characterized by presence of autoantibodies, hypergammaglobulinemia, typical liver histology and response to immunosuppressive therapy. Progression to cirrhosis occurs in 30% of cases. Autoimmune hepatitis (AIH) can have an acute severe presentation including acute liver failure that can be mistaken for a viral or toxic hepatitis. Pathogenesis of autoimmune hepatitis, clinical features of autoimmune hepatitis, laboratory investigation, important things to know about autoimmune hepatitis, diagnostic difficulties, scoring system, histopathology, types of autoimmune hepatitis, microscopy of autoimmune hepatitis, autoimmune liver disorders in children, autoimmune pediatric liver disease, and autoimmune acute liver failure are covered in this chapter.