Oxidative stress is a key factor in chronic diseases such as cancer, cardiovascular, neurodegenerative and metabolic disorders such as diabetes. Antioxidants, whether endogenous or derived from natural sources, neutralize Reactive oxygen species (ROS), mitigate cell damage, and promote health. This review examines the role of natural antioxidants, including phenolic compounds, vitamins, carotenoids, and omega-3 fatty acids, in preventing and treating disease. Phenolic compounds such as flavonoids and anthocyanins have significant antioxidant and anti-inflammatory potential and modulate various signaling pathways. Vitamins A, C, and E have unique antioxidant mechanisms that improve immune function and reduce oxidative damage. Carotenoids such as β-carotene and lycopene offer protective effects against various chronic diseases. The eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) significantly reduce inflammation and oxidative damage. Despite the promising benefits, limitations in bioavailability and stability hinder their therapeutic potential, so advances in delivery systems, such as nanotechnology-based formulations, are needed. By integrating natural antioxidants into clinical and dietary therapies, their potential to attenuate oxidative stress and manage chronic diseases opens up opportunities for innovative treatment strategies.