At the center of the U.S. Justice Department’s response to America’s substance abuse crisis is the Bureau of Justice Assistance’s (BJA’s) Comprehensive Opioid, Stimulant, and Substance Abuse Program (COSSAP). Grantees under this program are mandated and assisted in creating local and state partnerships that involve collaboration to address substance abuse across agencies charged with serving public health, behavioral health, and public safety. COSSAP resources have supported innovative efforts to prevent and treat substance abuse in large cities, rural communities, tribal lands, and U.S. territories. Nearly 300 site-based projects and demonstration sites have committed to and received resources to design and implement programs that reflect the collaborative model for preventing and treating substance abuse disorders. An additional cohort of just over 100 site-based grants are expected to be awarded by early fall 2020. The COSSAP TTA program supports jurisdictions that need help in implementing the COSSAP model. Expertise is available to meet the specific needs and goals of a wide range of strategies, including law enforcement and first-responder diversion strategies; overdose prevention; reentry and community corrections; peer recovery support services; cross-site coordination; rural and tribal planning and capacity building; services for children and families victimized by the crisis; and prescription drug monitoring programs. Guidance is also provided for various types and means of treatment. TTA providers are listed and described, and guidance is provided for requesting COSSAP TTA resources.