Due to their high persistence in the environment and adverse health efffects in humans, the use of many legacy per- and polyfluoroalkyl substances (PFAS) has been restricted. Thus, novel PFAS are increasingly used for numerous industrial applications, despite the fact that currently limited or no data is available on their toxicity. This study aims to examine the molecular mechanisms of action of novel PFAS by whole transcriptome analysis and by using differentiated HepaRG cells as a model for human hepatocytes. The focus is on the subgroup of mono- and polyether PFAS, with both linear and branched structures, including PFAS congeners with either a carboxylic acid or a sulfonic acid functional group.