The present study was performed to investigate the potential effects of the unripened dried fruit of Rubus coreanus Miq., Rubi Fructus (RF), on hepatic steatosis and lipid metabolism in mice fed with a high-fat diet (HFD) known to induce obesity and hyperlipidaemia. Rubi Fructus extract (RFex) fed mice demonstrated a reduced body weight and adipose tissue weight. RFex fed mice also demonstrated decreased aminotransferase levels, lipid contents [triglyceride (TG), total cholesterol (TC) and low-density lipoprotein-cholesterol (LDL-C)], leptin content and increased high-density lipoprotein-cholesterol (HDL-C) contents in the plasma. These effects were accompanied by a decreased expression of lipogenic genes, including sterol regulatory element binding protein-1c, liver X receptor, fatty acid synthase (FAS), acetyl-CoA carboxylase, cluster of differentiation 36, lipoprotein lipase and decreased lipogenic enzyme FAS and 3-hydroxy-3 methylglutamyl coenzyme reductase enzyme activities, while elevating carnitine palmitoyltrasferase-1 activity. Based on these results, the present study hypothesized that the inhibitory effect on hepatic steatosis of RFex is the result of the suppression of lipid synthesis in mice fed with HFD, suggesting that RFex may be beneficial in preventing hepatic steatosis and liver lipotoxicity.