Liver fibrosis is an important human health issue associated with chemical exposure. It is a typical result of chronic toxic injury and one of the considered endpoints for regulatory purposes. This AOP describes the linkage between hepatic injury caused by protein alkylation and the formation of liver fibrosis. Fibrogenesis is a long-term and complex process for which an adequate cell model is not available and an in vitro evaluation of fibrogenic potential is therefore not feasible yet. This systematic and coherent display of currently available mechanistic-toxicological information can serve as a knowledge-based repository for identification/selection/development of in vitro methods suitable for measuring key events and their relationships along the AOP and to facilitate the use of alternative data for regulatory purposes. Identified uncertainties and knowledge gaps can indicate priorities for future research.