Objectives: To determine the mode of hypolipidemic action of Hulled Barley Grains Powder (HBGP) on the gene level expression of PPAR-γ and SIRT1 in High-Fat Diet (HFD) induced hyperlipidemic rats. Methods: The HBGP was subjected to High-Performance Liquid Chromatography (HPLC) to quantify the major phytochemicals. Male Sprague Dawley rats were fed an HFD for 14 weeks to induce hyperlipidemia. The rats in groups 1 and 2 were fed a standard diet. Group 3 and 4 rats were fed HFD for 14 weeks. From the third week onwards, Group 2 and 4 rats received 50% of HBGP mixed in the feed, in addition to 50% of the normal and HFD diets. The rats were euthanized after 14 weeks, and plasma lipids, serum levels of adiponectin and leptin were measured. The mRNA expression of PPAR-γ and SIRT1were also measured. Findings: HBGP was found to contain phenolics: Ferulic acid-9.11, benzoic acid-3.58, cinnamic acid-1.191, vanillic acid-2.43, flavonoids: quercetin-6.53, kaempferol-1.04, and myricetin-1.443 (mg/g). HFD+HBGP fed rats showed a significant decrease in blood lipids and leptin levels. Furthermore, serum adiponectin levels and mRNA expression of PPAR-γ and SIRT1 were found to be quantitatively increased in HBGP co-administered rats when compared to HFD fed rats. Novelty: HBGP exhibits hypolipidemic activity by elevating the mRNA expression of PPAR-γ and SIRT1. The presence of various phytochemicals such as ferulic acid, quercetin, benzoic acid, vanillic acid, myricetin, cinnamic acid, and kaempferol might be accounted for the hypolipidemic effect of HBGP.