Diabetes mellitus is a chronic metabolic condition that is marked by hyperglycemia, insulin resistance, and compromised pancreatic beta-cell functionality. Traditional approaches to anti-diabetic treatment are typically limited by insufficient solubility, bioavailability, frequency of administration, and safety, causing poor therapeutic results. Nanotechnology-based drug delivery systems have become a promising approach to conquer these hurdles by enhancing solubility, stability, delivery by targeting, and release of drugs. Various nano-formulations, such as polymeric nanoparticles, solid lipid nanoparticles, liposomes, dendrimers, nano-emulsions, and herbal-based nanoparticles, are identified in this review and have been applied in the delivery of specific anti-diabetic agents, including metformin, insulin, glibenclamide, pioglitazone, sitagliptin, and bioactive herbal compounds, such as curcumin and berberine. The main points of discussion are mechanisms of action, targeting strategies, pharmacokinetics, pharmacodynamics, evaluation parameters, clinical status, regulatory considerations, and prospects, including personalized and glucose-responsive nanomedicine. Combining nanotechnology with smart drug delivery systems can improve therapeutic effect, minimize side effects, enhance patient compliance, and offer precision medicine strategies for diabetes treatment. This overview highlights how nano-formulations can revolutionize traditional diabetes treatment and pave the way for next-generation, patient-centric therapies.