**Abstract**

Obesity is a very common issue worldwide, and it is one of the risk factors for mortality. Several studies were done to identify the causes of this issue and to investigate factors that can affect this condition. Vitamin D is claimed to have an impact not only for maintaining bone health but also for having an association between its deficiency and obesity as some studies found that the concentrations of this vitamin are low in obese individuals. The suggested mechanisms and a discussion of the latest findings as well as the possibility of integrating supplementation in the treatment of obesity are covered in this book chapter. It was concluded that vitamin D deficiency is prevalent in many parts of the world and the supplements are an affordable option, but further studies are required to address different confounding factors that will result in clear data interpretation and will contribute to the future planning of health policies and guidelines used by healthcare professionals.

**Keywords:** vitamin D, deficiency, supplements, obesity, health, BMI
