The purpose of Guidelines for Successful Transition of People with Mental and Substance Use Disorders from Jail and Prison: Implementation Guide is to provide behavioral health, correctional, and community stakeholders with examples of the implementation of successful strategies for transitioning people with mental or substance use disorders from institutional correctional settings into the community. This guide serves as a direct successor to the 2013 publication Guidelines for the Successful Transition of People with Behavioral Health Disorders from Jail and Prison (Blandford & Osher, 2013), a collaborative product of the SAMHSA’s GAINS Center with the Council of State Governments Justice Center, and the 2002 report A Best Practice Approach to Community Re-Entry from Jails for Inmates with Co-Occurring Disorders: The APIC Model (Osher, Steadman, & Barr, 2002). The guide is intended to promote jurisdictional implementation of the APIC Guidelines through the identification and description of various jurisdictional strategies that have been adopted in efforts to facilitate successful community reentry for justice-involved people with mental and co-occurring substance use disorders.