“The disproportionate number of people with behavioral health disorders involved in the criminal justice system puts a tremendous strain on scarce public resources and has a huge impact on health care and criminal justice budgets. This research summary demonstrates that with appropriate treatment and access to community-based services, this population is less likely to be incarcerated and more likely to lead healthy, productive lives-while resulting in substantial costs savings. Sections of this publication include: introduction; scope of the problem; treatment alternatives to incarceration, how they work, and how they save money-prevention, jail diversion, courts, community reentry planning, and opportunities under the Affordable Care Act (ACA).