ADHD frequently co-occurs with substance use disorder (SUD) and is also common in prison populations. Screening and structured diagnosis should therefore be made available to treatment seeking SUD patients as well as to prison inmates. Multimodal, integrated treatment, including appropriate pharmacological and psychosocial therapies, is recommended for both ADHD and SUD. Long-acting stimulants with lower misuse potential are first line treatment for ADHD, with research indicating that somewhat higher stimulant doses could be necessary in this population. Increased frequency of underlying cardiovascular conditions, as well as increased risks for medication misuse in SUD populations, warrant careful treatment monitoring. There is no evidence suggesting that stimulant treatment increases risk for SUD. Given its high prevalence in prison settings, diagnosis of and integrated pharmacological and psychosocial treatment  for ADHD may decrease SUD relapse and criminality in those incarcerated.