Conceptions of mental illness in children are bound by cultural and social conventions of what constitutes healthy and unhealthy development. To understand current conceptualizations of disorders in children, we review the history of these conceptualizations from three intertwined perspectives: a sociopolitical history of American children and families, the history of the mental health fields and scientific disciplines involved in diagnosing children, and the evolution of children's role in the Diagnostic and Statistical Manual of Mental Disorders. We review where the field has been in its conception of childhood mental illness throughout the past century, where we believe it is now, and raise questions about the direction in which child diagnosis may be headed as we enter the new millennium. We conclude with social policy recommendations based on theory and research regarding mental disorders in children.