Background: Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by persistent hyperglycemia, oxidative stress, and inflammation, contributing to insulin resistance and long-term complications. Dietary antioxidants from plant sources, such as polyphenols, flavonoids, carotenoids, and phenolic acids, have been increasingly studied for their potential to modulate these pathophysiological mechanisms. Objective: This review aims to summarize and critically analyze the current evidence on the biological effects, therapeutic potential, and translational challenges of plant-derived antioxidants in the prevention and management of T2DM. Methods: This narrative review was conducted using peer-reviewed literature from PubMed, Scopus, and Web of Science. Emphasis was placed on mechanistic studies, clinical trials, bioavailability data, and advances in formulation technologies related to antioxidant compounds in the context of T2DM. Results: Plant antioxidants exert beneficial effects by modulating oxidative stress, reducing systemic inflammation, and improving insulin signaling pathways. However, their clinical application is limited by low bioavailability, chemical instability, and high interindividual variability. Recent developments, such as nanoencapsulation, synergistic functional food formulations, and microbiome-targeted strategies, have shown promise in enhancing efficacy. Additionally, personalized nutrition approaches and regulatory advances are emerging to support the integration of antioxidant-based interventions into diabetes care. Conclusions: Plant-derived antioxidants represent a promising complementary tool for T2DM management. Nonetheless, their effective clinical use depends on overcoming pharmacokinetic limitations and validating their long-term efficacy in well-designed trials. Integrating food technology, microbiome science, and precision nutrition will be crucial to translate these compounds into safe, scalable, and personalized therapeutic options for individuals with or at risk of T2DM.