Insulin resistance is a risk factor for metabolic disease including type 2 diabetes and dyslipidemia that is induced by obesity associated chronic inflammation and oxidative stress. Therefore, the treatments of the inflammation and/or oxidative stress are important to improve the insulin resistance. Acanthopanax Senticosus (Rupr. et Maxim) Harms (Goka) has been applied to traditional Chinese medicine, due to its anti-inflammatory and anti-oxidative effects (though detailed information are not available to date). Thus, Goka might lead to the improvement in the status of insulin resistance. The aim of the present study was to investigate whether Goka fruit (GF) improves insulin resistance via the suppression of inflammatory mediators and oxidative stress. After eight weeks induction of high-fat diet, mice were divided into four groups; vehicle (HFD), HFD-GF (500 mg/kg and 1000 mg/kg), and HFD-metformin (MET) (300 mg/kg) for 12 weeks of oral administration, respectively. Insulin tolerance test revealed that HFD-GF groups significantly decreased plasma glucose level than HFD. HFD-GF group exhibited significant reduction of hepatic lipid accumulation rather than HFD. In the adipose tissues, expression of cyclooxygenase-2 (COX-2) and tumor necrosis factor-alpha (TNF-α) were tend to decreased by HFD-GF administration rather than HFD. Thiobarbituric acid reactive substance (TBARS) in HFD-GF were tend to lower than that of the HFD group. These results suggest that GF improved the HFD induced insulin resistance through the alleviate obesity associated inflammation and oxidative stress in the peripheral tissue.