The aim of the study was to review the current literature on the role of vitamin D in dentistry. The term vitamin D is defined as a group of compounds which are cholesterol derivatives with a similar chemical structure. It is produced in the human body and passes through many stages of synthesis. Vitamin D affects our body through the immune, muscular, nervous, and cardiovascular systems. It is also relevant in dentistry and in the carbohydrate metabolism. Nowadays, vitamin D deficiency levels are high in both the Polish and the world population as a whole. This is due to many factors: latitude, diseases and lifestyle. The data shows that over 90% of people of color (black, Latino, Asian, etc.) and nearly 3/4 of whites living in the United States suffer from a shortage of 25-hydroxycholecalciferol (25(OH) vitamin D). Meanwhile, studies performed in Poland report that a concentration of vitamin D <20 ng/mL (50 nmol/mL) occurs in 70% of the population. Preliminary reports suggest that vitamin D, through the maintenance of normal bone metabolism, as well as its antibacterial and anti-inflammatory activity, modulates periodontal disease. A normal level of vitamin D is important in the treatment of periodontitis. More and more studies are focusing on the problem of vitamin D deficiency and its role in the human body. It is very important to maintain normal levels of vitamin D in the blood and supplement it in the case of shortfalls.