Attention-deficit/hyperactivity disorder (ADHD) is the one of the commonest neurodevelopmental conditions, and has strong genetic and neurological underpinnings. The article explains the aetiology (includes both genetics and environmental factors), method of assessment and diagnosis as well as multidisciplinary management (includes medication and behavioural modification programme). A home-based and school-based behavioural modification strategy together with medicines is the best approach to ensure good developmental outcome.