This chapter introduces the reader to the need for a developmental approach and the challenges involved in diagnosing this neurodevelopmental disorder in children, the related clinical and research implications, and how to make a differential diagnosis. It then describes relevant developmental, environmental, and genetic risk factors during the perinatal period, infancy, and childhood. The next section reviews the impaired cognition, social cognition, and self‐disturbance that occur during the illness. A detailed review of structural imaging findings sheds light on the developmental mechanisms underlying the multiple areas of functional impairment and associated symptoms found in youth with schizophrenia. After briefly reviewing the findings of functional imaging and genetic studies, the chapter describes the treatment and course of the disorder. The concluding section emphasizes the need for future studies on the epidemiology, outcome, clinical markers, gene‐psychosocial risk factors, treatment modalities, and neural circuits underlying the developmental impact of the disorder's extensive functional impairment.