Evidence suggests that vitamin D supplementation could potentially be effective either in treatment or prevention of coronavirus disease 2019 (Covid‐19). Indeed, several studies and trials have begun to investigate the impact of vitamin D supplementation on patients with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection. In this review, we focus on the potential mechanisms of vitamin D in the pathogenesis of Covid‐19. We consider whether deficiency of vitamin D may be one of the underlying biological factors that could explain the excess mortality seen among non‐Caucasians. We also raise several important questions which need to be addressed to provide a clear picture of the extent to which vitamin D supplementation may benefit patients with Covid‐19, particularly those with underlying risk factors.