Attention deficit hyperactivity disorder (ADHD) is characterised by a combination of symptoms including inattention, hyperactivity/ impulsivity, as well as overall problems with executive functioning and the ability to self-regulate. Hyperactivity and impulsivity symptoms are often related to externalising and are associated with behavioural problems later in life. The expression of these core ADHD symptoms may have a strong link with delinquency and criminality. Inattentiveness may also play a role in a delinquent trajectory, taking place through low educational attainment and functional deficits in daily living. In this context, it is not surprising that adolescents and adults with ADHD abound in correctional services worldwide, and come into contact with the criminal justice systems more often than individuals without the disorder. Here, we review the latest findings regarding the links between ADHD and offending behaviours, and the most recent international prevalence rates of the disorder in prisons. In addition, the implications of having ADHD and its main comorbidities in the criminal justice system, and the role of treatment in this setting are discussed.