Acute liver disease or failure in children is the result of viral hepatitis (A, B, E or sero-negative), indeterminate hepatitis or inherited metabolic liver disease. The clinical presentation includes jaundice, coagulopathy and encephalopathy. Uncomplicated acute hepatitis resolves spontaneously, but progressive acute liver failure is fatal in 70% of cases and requires referral to specialized units, to prevent complications and for consideration for liver transplantation. Chronic liver disease may result from unresolved neonatal liver disease, due to either inherited cholestasis or α1-antitrypsin deficiency. Chronic viral hepatitis B and C are rare but significant diseases for which there is now effective therapy. Treatment for hepatitis B is still evolving, but the new direct-acting antivirals are highly successful in adults with hepatitis C and will soon be in clinical trials in children. In older children, autoimmune liver disease, non-alcoholic steatohepatitis or cystic fibrosis are the commonest causes. Treatment includes specific medication, nutritional support and liver transplantation for end-stage disease. The long-term outcome of liver transplantation is excellent, more than 80% surviving for 15–20 years with good quality of life, although outcomes following transition to adult services could be improved.