This article reviews the normal development of sleep in infants, children, and adolescents, with specific focus on both the subjective and objective aspects of sleep. Notably, sleep duration decreases substantially from infancy through adolescence with increased consolidation of sleep to the nighttime period only. Sleep architecture exhibits developmental changes with decreases in slow-wave sleep and increases in stage 2 sleep from childhood through adolescence. Although the development of sleep is a dramatic and relatively rapid process during the first decades of life, changes in sleep continue across the life span.