Nonalcoholic fatty liver disease (NAFLD) is a chronic con dition affecting one quarter of the global population. Although primarily linked to obesity and metabolic syn drome, undernutrition and the altered (dysbiotic) gut microbiome influence NAFLD progression. Both undernu trition and NAFLD prevalence are predicted to considerably increase, but how the undernourished gut microbiome contributes to hepatic pathophysiology remains far less studied. Here, we present undernutrition conditions with fatty liver features, including kwashiorkor and micro nutrient deficiency. We then review the gut microbiota-liver axis, highlighting key pathways linked to NAFLD progres sion within both overnutrition and undernutrition. To conclude, we identify challenges and collaborative possi bilities of emerging multiomic research addressing the pa thology and treatment of undernourished NAFLD.