IL11 contributes to the development of non-alcoholic steatohepatitis (NASH) through incompletely understood mechanisms. Here, the authors report that lipotoxicity-driven autocrine IL11 activity underlies hepatocyte metabolic dysfunction and death via a NOX4/ERK-mediated mechanism while paracrine IL11 activity stimulates hepatic stellate cells contributing to fibrosis and inflammation in the context of NASH.