Vitamin D plays an important role in calcium homeostasis and bone health, modulation and regulation of inflammation, immune function, cell growth, neuromuscular function, and glucose metabolism. Due to several modifiable and nonmodifiable factors, vitamin D deficiency (VDD) is common in children in both developed and developing countries. Rickets is a common manifestation in children with VDD. Diagnosis of rickets and VDD relies on dietary intake, sunlight exposure, vitamin D supplementation, clinical features of rickets, and measurement of serum 25-hydroxy vitamin D [25(OH)D] levels. The treatment and prevention of VDD include vitamin D supplementation, food fortification, and adequate exposure to sunlight.