This chapter reviews pediatric sleep–wake disorders, with a particular focus on evaluation and treatment of sleep disturbances comorbid with primary psychiatric disorders and commonly prevalent primary sleep disorders in the pediatric population. The sleep disturbances due to primary sleep disorders can often result in symptoms and behaviors suggestive of a psychiatric condition such as inattention, poor impulse control, academic impairment, mood changes, fatigue, and excessive daytime sleepiness. It is important that the pediatric clinician assesses the youth presenting with sleep and psychiatric symptomatology for presence of primary sleep disorders. Consultation with a sleep physician for further evaluation and treatment is recommended if a primary sleep disorder is suspected. More evidence-based treatments are needed for primary insomnia and sleep disturbances comorbid with primary psychiatric disorders in pediatric population.