Obesity is a risk factor for numerous metabolic diseases. Recently, naturally occurring compounds that may improve obesity have received increasing attention. Xanthigen is a mixture of fucoxanthin and punicic acid derived from brown seaweed and pomegranate seed, respectively, which have been traditionally used for lipid-lowering effects in humans. In this study, we investigated whether Xanthigen attenuates high-fat diet-induced obesity in C57BL/6N mice. The mice were fed on a normal diet (ND), high-fat diet (HFD), HFD plus 1% Xanthigen or HFD plus 1% green tea extract (GTE) for 11 weeks. Food efficiency ratio (FER) and body weight were significantly reduced in mice fed HFD plus Xanthigen compared to HFD-fed mice. Consistent with the results in body weight change, Xanthigen also significantly decreased the weights of epididymal adipose tissue, retroperitoneal adipose tissue, and liver in HFD plus 1% Xanthigen-fed mice. The serum level of low-density lipoprotein (LDL)-cholesterol was significantly decreased in HFD plus Xanthigen-fed mice compared to HFD-fed mice. These results suggest that Xanthigen may be useful in the development of a functional health food for anti-obesity.