The geriatric population is characterized by wide ranges of age (60 years onwards), type of ageing (successful and unsuccessful), comorbidities, polypharmacy, and reduced mobility, but paradoxically, with the improvement in medical sciences, the lifespan of an average human being is still increasing. In this backdrop, it is absolutely essential to explore the role of vitamin D in the said population and lay down guidelines which shall help medical professionals to rationalize its supplementation in the said population. This chapter discusses the prevalence of vitamin D deficiency in the elderly, effect of ageing on vitamin D metabolism, effects of vitamin D deficiency with its various drug interactions, and its preventive and treatment strategies.