Vitamin D is essential for intestinal absorption of calcium and phosphate, as well as for maintaining good muscle performance and optimal immune function. In fact, consistently low vitamin D levels impair skeletal mineralisation and increase the risk of bone fractures. Among these, stress fractures, caused by repeated mechanical stress, have been associated with vitamin D deficiency and are a common problem among athletes and military personnel. Correcting and maintaining adequate vitamin D levels, together with optimising calcium levels, is one of the most effective strategies for strengthening the skeleton and, consequently, preventing the risk of fractures. Therefore, this review offers an overview of the mechanisms by which vitamin D affects bone health and post-traumatic recovery, providing a solid basis for future research and clinical interventions.