Summary: Vitamin D is a “Holy Grail” in the treatment of many diseases, including respiratory tract infections regardless of severity. During the COVID-19 pandemic, some information might suggest that this pleiotropic hormone may play an important role in susceptibility to SARS-CoV-2 infection and in the clinical course of the disease. In this short review the authors summarize the data about vitamin D’s mechanism of action and its possible role in protection from coronavirus infection and a severe course of COVID-19. A clinical recommendation suggesting vitamin D supplementation during the pandemic is also given.