RTI International’s role in COSSUP is to provide direct support to state agencies and subrecipients, making communities safer by promoting evidence-based practices to respond to illicit substance use and misuse across all government levels. Through its substantive, methodological, and technical assistance expertise, RTI and its partners foster peer-to-peer learning and cross-site coordination to enable discussions of lessons learned, facilitate program improvements, and promote evidence-based program proliferation, providing tailored training and technical assistance for the unique needs of jurisdictions that can also be applied nationally.