Sleep-wake problems are common during childhood and adolescence. They are of diverse cause, and can contribute significantly to alterations in behavior, cognition, and learning. Obstructive sleep apnea, central hypoventilation syndrome, narcolepsy, periodic hypersomnia, delayed sleep phase syndrome, restless legs syndrome, parasomnias, and sleep disruption consequent to psychiatric disorders are some of the commonly encountered conditions. Some aspects of sleep architecture and its organization change with age and maturation. Diagnostic criteria and sleep laboratory techniques and findings for some childhood sleep disorders differ from those of adults. Most pharmacologic agents used to treat pediatric sleep disorders are off-label.