Vitamin D, obtained from food or synthesized in the skin through sun exposure, plays a vital role in various physiological processes. This review focuses on cholecalciferol (vitamin D3), specifically its production from 7-dehydrocholesterol in the skin. The aim is to evaluate the impact of vitamin D on the development of atherosclerosis and other pathological conditions. Atherosclerosis, a chronic vascular inflammation caused by innate immunity, is of particular interest. Understanding the role of vitamin D in reducing inflammation and oxidative stress holds significant implications for effective treatment strategies. Deficiency of vitamin D has been observed in individuals with cardiovascular disease, ischemic stroke, and myocardial infarction. Hypovitaminosis D is also suspected to contribute to vascular calcification, a factor closely associated with cardiovascular morbidity and mortality. Investigating the multifaceted effects of vitamin D on various pathophysiological processes is thus crucial.