This study evaluated the effects of the preharvest application of 0.2 g/L gibberellin A3 (GA₃) or 0.02 g/L forchlorfenuron (CPPU) at full bloom on postharvest storability and defense responses in ‘Brightwell’ blueberry. After ripening, berries were inoculated in vitro with a defined mixture of postharvest fungal pathogens. Fruit quality attributes and physio-logical indices were monitored during storage, and LC-MS metabolomics was performed to characterize treatment-associated metabolic alterations.GA₃-treated fruit exhibited higher antioxidant capacity and a lower decay incidence than CPPU-treated and control fruit. Metabolomic profiling showed that GA₃ was associated with the accumulation of specific polyphenols, coinciding with enhanced resistance to postharvest pathogens. In parallel, GA₃ treatment modulated glycerolipid metabolism and mitigated membrane lipid peroxidation, as indicated by reduced malondialdehyde levels, while enhancing enzymatic (superoxide dismutase and ascorbate peroxidase) and non-enzymatic (poly-phenol) antioxidant defenses. Overall, these results suggest that preharvest GA₃ application can improve blueberry storability by coordinating redox homeostasis and lipid-related metabolic remodeling.