Fruits are rich in fiber and antioxidant compounds that can prevent and treat health disorders related to oxidative stress caused by high-fat high-cholesterol diet (HFHCD). Bouea macrophylla is a tropical fruit plant with edible juicy fruits. In this study, we conducted experiments to prove the effectiveness of B. macrophylla fruit juice (BMFJ) as an antioxidant agent in rats fed with HFHCD. Male Sprague Dawley rats were fed with HFHCD for 100 days and simultaneously orally supplemented with BMFJ. Atorvastatin was used as a positive control. At the end of the experiment, the blood and hepar were collected and assayed for malondialdehyde (MDA). The in vitro antioxidant activity of BMFJ was also evaluated using the DPPH method. Total phenols and flavonoids contents were determined using Folin Ciocalteu and AlCl3 methods, respectively. Results of the experiments showed that total phenols and flavonoids in BMFJ were 570 mg GAE/g and 31.89 mg QE/g, respectively, and the IC50 of radical scavenging activity was 564.271 ppm. The in vivo antioxidant evaluation showed that supplementation of BMFJ significantly prevents the increase of MDA levels, both in serum and liver of rats fed with HFHCD. These findings clearly indicate that supplementation of B. macrophylla fruit juice significantly prevents oxidative stress in rats fed with high-fat high-cholesterol diets through attenuation of lipid peroxidation.