In children’s psychological disorders the interplay of heredity and environment, within culture, family and school, shapes the clinical presentation. Assessment strategies must address this complexity. Diagnostic classification may include categories that describe psychosocial functioning. Problems of early child development often reflect parenting problems. Physical illness leads to raised risk of psychiatric disorder and coping may be maladaptive. There is great variety in the aetiology and presentation of childhood disorders (Emotional Disorders, Medically Unexplained Symptoms, Enuresis, Encopresis, Attention Deficit Hyperkinetic Disorder (ADHD), Conduct Disorder, Eating Disorder and Psychosis). A range of physical, emotional or behavioural symptoms may require assessment and diagnostic formulation that will guide psychological and pharmacological treatment approaches. Common problems of neuro-development include communication disorders, motor disorders, specific learning difficulties and learning disability. Legal frameworks determine professional responses to offending by children and to child abuse.