Vitamin D research suggests it has a role in disorders other than bone metabolism. Objective: To update the information on vitamin D deficiency (VDD) in pediatric clinical disorders. Methods: Search in virtual libraries, giving priority to clinical and longitudinal studies and meta-analyses on VDD in the pediatric age group published in the past 20 years. The terms "vitamin D deficiency", "children and adolescents" (both in Spanish and English) were used as search descriptors. Results:In the pediatric population, VDD is associated with different clinical diseases, such as bone alterations, insulin resistance, metabolic syndrome, respiratory tract infections, asthma, and autoimmune diseases. Besides, it is associated with prematurity, obesity, malabsorption, use of anticonvulsant agents, and lifestyle characteristics, such as clothing, extreme latitudes, low consumption, and little sun exposure. Conclusions: According to the evidence, VDD is highly prevalent in several disorders and diseases in the pediatric age group. The recommendation is to prevent VDD in risk conditions and to maintain 25(OH)D serum levels > 75 nmol/L.