Introduction: The aim of the current study is to evaluate the antihyperlipidemic and antioxidative effects of hydro-alcoholic extract of marjoram (HAEM) in rats fed with a high-fat diet (HFD). Methods: In the experimental study, the rats were randomly divided into four groups of five rats in each and fed with high-fat diet for 12 weeks as follows: One group (normal diet group) was fed with a standard diet, one group was fed with HFD, and two groups were fed with HFD and orally fed with 150 and 450 mg/kg/day HAEM. The serum samples and liver tissues were used for measuring the biochemical and oxidative parameters and histopathological studies. HFD induced hepatosteatosis in rats as evidenced by the altered liver enzymes activity, serum lipid profile and oxidative status. Results: Serum lipid profile (triglyceride, cholesterol and low-density lipoprotein) in rats fed with HFD + HAEM (150 and 450 mg/kg/day) was significantly decreased. Furthermore, the evaluation of oxidative stress showed a reduction of the malondialdehyde (MDA) level and an increase in ferric-reducing anti-oxidant power. Meanwhile, liver enzyme activities declined in response to HAEM. Conclusion: Using the HAEM could be a future therapeutic agent in treating hepatosteatosis and reducing oxidative damages of HFD in the liver.