This entry aims to provide a general overview of Attention Deficit Hyperactivity Disorder (ADHD). Currently, ADHD is one of the most common neurodevelopmental disorders in childhood and adolescence. Without timely detection and treatment, it can have adverse consequences for the child, because it affects their academic, social, family, and personal functioning. Therefore, first the various symptoms for diagnosis are presented, considering the main areas affected, such as attention, hyperactivity, and impulsivity. It also outlines the different subtypes of ADHD and their respective characteristics. Then, general guidelines are provided for assessment that aid in identification. Finally, a section is included that briefly describes treatment alternatives.