Objectives: Non-alcoholic fatty liver disease (NAFLD) is one of the major causes of liver disease worldwide. Although various molecular mechanisms are effective in the initiation and progression, the exact pathway is not completely clarified. Recent findings suggest a role of the endocannabinoid system in the pathology of NAFLD. Inulin has been shown to be beneficial for NAFLD. With the first study, we investigated the effects of inulin supplementation on NAFLD via the endocannabinoid system in Wistar rats fed high-fat diet. Methods: Male Wistar rats were fed with control, control plus inulin, high-fat, and high-fat plus inulin diets for 12 wk. Inulin was added to diets in 15% weight/weight. Biochemical parameters, insulin, and adiponectin levels were determined. Steatosis, lobular inflammation, and total NAFLD activity scores (NAS) were deter-mined by histopathological analysis and by magnetic resonance imaging. Anandamide and 2-arachidonylgly-cerol levels were measured by the liquid chromatography-tandem mass spectrometry method. Gene expression levels were determined by the quantitative polymerase chain reaction method. Results: Our results showed that the NAS of the high-fat diet was 4.16 0.30, which was significantly higher than that of the other groups. Inulin decreased Homeostasis model assessment measuring insulin resistance (HOMA-IR), serum triacylglycerol, total cholesterol, and Aspartate aminotransferaselevels. Inulin also signifi-cantly decreased Cannabinoid receptor-1 and Patatin-like phospholipase-3 gene expressions in the liver. The 2-arachidonylglycerol levels in the liver were lower in the inulin-added groups. These effects of inulin were associated with NAS. Conclusions: Inulin prevented the development of NAFLD, possibly by affecting the expression of genes involved in the pathogenesis of NAFLD in the liver via endocannabinoids. The results of this study show that inulin may be a promising molecule in the treatment/prevention of NAFLD. (c) 2022 Elsevier Inc. All rights reserved.