Vitamin D is essential to maintaining calcium and phosphate homeostasis and bone health. Many children do not achieve an adequate vitamin D status due to insufficient sunlight exposure and poor dietary intake. Vitamin D deficiency is common, affecting approximately 50% of children and adolescents. It is recommended to screen for vitamin D deficiency in patients at risk. Initial vitamin D supplementation dosage and frequency of administration are dependent upon the serum 25-hydroxyvitamin D concentration and what will maximize medication compliance. Cholecalciferol is preferable to ergocalciferol as the former is more potent. Once replete, almost all patients require some maintenance vitamin D to maintain sufficient 25-hydroxyvitamin D levels. Reasons to refer to a pediatric endocrinologist include if there is concern for sequelae of vitamin D deficiency, such as rickets or hypocalcemia; the inability to increase the 25-hydroxyvitamin D level into the sufficient range in compliant patients, and following dose escalation.