Currently, several studies have demonstrated that cold stress can cause the accumulation of reactive oxygen species (ROS) in fruit. However, little is known about the roles of gibberellic acid (GA₃) on the antioxidant system in the mitochondria of fruit. To explore the molecular basis of GA₃ interference with the chilling tolerance of fruit, ‘Jinqiuhongmi’ peach fruit was treated with 0.1 mmol L⁻¹ GA₃ after harvest. Exogenous GA₃ treatment relieved the chilling injury of postharvest peach fruit with a lower cold injury index and higher antioxidant level. In addition, GA₃ delayed the senescence of peaches by reducing the firmness, respiratory action, and ethylene production. The antioxidant enzyme activities were elevated, including superoxide dismutase (SOD) and catalase (CAT). Moreover, GA₃-treated peaches exhibited lower hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) in comparison with the control. These results showed that the application of 0.1 mmol L⁻¹ of GA₃ enhanced the chilling resistance of peach fruit by regulating the antioxidant system.