Diabetes mellitus (DM) is a chronic metabolic disorder characterized by persistent hyperglycemia due to impaired insulin secretion, action, or both. One of the major complications of DM is the development of chronic, non-healing wounds such as diabetic foot ulcers (DFUs), which significantly increase the risk of infection and limb amputation. Hyperbaric oxygen therapy (HBOT), the medical use of 100% oxygen at elevated atmospheric pressure, has shown promise as an adjunctive treatment for selected diabetic complications. By increasing oxygen delivery to ischemic tissues, HBOT stimulates angiogenesis, enhances fibroblast and collagen activity, improves leukocyte-mediated bacterial killing, and supports epithelialization and tissue repair. Clinical studies suggest that HBOT can reduce healing time, prevent major amputations, and improve the overall prognosis in patients with refractory DFUs. While HBOT does not replace standard glycemic control or wound care, it can significantly improve outcomes when integrated into a comprehensive management strategy. Despite encouraging results, further randomized controlled trials are needed to establish standardized protocols and assess long-term cost-effectiveness.