Updated project metadata. Non-alcoholic fatty liver disease (NAFLD) is most prevalent form of liver disease, affecting over 30% of Americans. Perfluoroalkyl substances (PFAS) represent a family of environmental toxicants that have infiltrated the living world. This study explores diet-PFAS interactions and their potential role in the increasing global incidence of NAFLD. Male C57BL/6 mice were fed with either a low-fat diet (11% kcal from fat) or a high fat (58% kcal from fat) high carbohydrate (42g/L) diet with or without PFOS or PFHxS in feed (0.0003% w/w) for 29 weeks. Proteomic, lipidomic, and gene expression measurement techniques were utilized to explore mechanistic pathways. With administration of a high fat high carbohydrate (HFHC) diet, PFOS and PFHxS augmented macrovesicular steatosis, indicative of fatty liver. There was a clear shift in the lipidome of the serum phosphatidylcholines, phosphatidylethanolamines, and triglycerides with PFAS exposure. Finally, chain length exerted significant influence on tissue partitioning and the resulting hepatic gene and protein signatures of PFHxS and PFOS in vivo.