Objective: The purpose of this systematic review was to evaluate the role of and importance of Vitamin D deficiency as a risk factor for stress fractures in soldiers and athletes. Methods: A search of the current literature was performed, leading to the inclusion of 14 suitable papers for analysis. A search on EMbase conducted using the search items “Vitamin D deficiency” and “stress fracture” was performed. The outcomes of these papers were used to outline a better understanding of the role of Vitamin D deficiency as a risk factor for stress fractures in these unique patient populations. Results/Discussions: Often implicated in the pathophysiology of stress fractures, Vitamin D deficiency is described as a risk factor for the development of this condition in both athletes and military personnel, although the exact pathophysiology still requires further delineation. Conclusion: While sufficient intake and metabolism of Vitamin D is important for proper bone health and to attenuate the risks of stress fractures, the true impact of Vitamin D insufficiency and deficiency varies across different populations, including athletes and soldiers. Overall, large, long-term and prospective studies must be completed to further our current understanding of this important area of musculoskeletal medicine.