Background: The human development is a complicated process that is believed to be influenced by dietary, environmental, hormonal, and genetic factors. The main hormones involved in growth at every stage of development are growth hormone (GH) and its mediator, insulin-like growth factor 1 (IGF-1). On the other hand, vitamin D controls how calcium and phosphorus are metabolized, which is important for bone growth and mineralization. Despite a number of biochemical and clinical studies demonstrating a strong correlation, no scientific research has yet to elucidate their interaction, particularly in terms of how one malfunction impacts the other. Aim: to assess the role of vitamin D in growth hormone deficiency and the effect of GH therapy on vitamin D. Conclusions: vitamin D levels are often lower in the patients with GH deficiency (GHD) than in the controls. This condition may exacerbate the metabolic risk of GHD, which is already known to exist.