This study aimed to evaluate the antioxidant activity of punicalagin, which is extracted from the pomegranate, on the stability of olive oil in comparison with butylated hydroxytoluene (BHT). The evaluation was carried out by measuring peroxide value (PV) and acid value (AV) to identify the primary products of oil oxidation. Thiobarbituric acid reactive substances (TBARS) and P-Ansidine value (PAV) were used to identify the secondary products of oxidation. Also, the total oxidation index (TOTOX) was calculated to evaluate the overall oxidation status of olive oil samples. Olive oil was divided into three groups: olive oil alone (control), olive oil with BHT, and olive oil with punicalagin. All samples were stored in the same conditions and tested for 60 days. The presence of punicalagin in olive oil significantly reduced peroxides (18.17 Meq/kg oil; p< 0.0001), acid value (5.32 mg KOH/g fat, p< 0.0001), TBARS formation (3.22 ug MDA/g oil, p<0.01), and P-AV (13.82; p<0.0001) in comparison with the control (27.50 Meq/kg oil, 3.67 ug MDA/g oil, and 19.35, respectively). Also, the antioxidant activity exhibited by punicalagin showed similar effects as the synthetic antioxidant, BHT, with no significant differences between them in all parameters. These findings indicate substantial potential for using punicalagin as a natural preservative to improve the quality of oil during storage and to prolong its shelf life.