With this solicitation, OJJDP seeks to fund a training and technical assistance (TTA) provider to build capability and capacity of diversion programs serving justice-involved youth populations with substance use disorder and co-occurring mental health and substance use disorder needs. The successful applicant will lead a national TTA program and administer a subaward program providing subawards to local demonstration sites to improve responses and outcomes for youth with substance use disorders and co-occurring mental health and substance use disorders who come into contact with the juvenile justice system, or who are at high risk of contact, by diverting these youth toward community-based treatment to address their unique mental and behavioral health needs to prevent them from entering the formal justice system.