As peer practitioners move into professional roles in the criminal justice system, programs need to carefully plan and prepare to integrate peer supports into their portfolio of services. This Effective Integration Toolkit, developed by the Bureau of Justice Assistance's (BJA) Comprehensive Opioid, Stimulant, and Substance Abuse Program (COSSAP), provides an overview for effective integration, offers suggestions for organizations in how to best implement peer support in criminal justice settings, and includes a checklist to help inform next steps.