Non-alcoholic fatty liver disease (NAFLD) is the most common liver disorder in children and has the potential to progress to advanced fibrosis/cirrhosis, end-stage liver disease and hepatocellular carcinoma. However, the natural history of the condition is poorly understood and there are no approved treatments. The European Paediatric Non-Alcoholic Fatty Liver Disease Registry (EU-PNAFLD) is a multi-centre registry of paediatric NAFLD that will serve as a prospective, observational, natural history study and provide a tractable back-bone to support recruitment into subsequent interventional trials. Collection of samples into a bio-repository will facilitate translational studies, including genome sequencing and metabolomics. EU-PNAFLD will work closely alongside the existing adult European NAFLD Registry to obtain data on clinical outcomes after 20-30 years. Through an international, well-characterised large-scale cohort, EU-PNAFLD will address the key questions in paediatric NAFLD and benefit patients with the condition.