This brief provides information on the Mental Health Training Curriculum for Juvenile Justice (MHTC-JJ), which was developed by the Models for Change Mental Health/Juvenile Justice (MH/JJ) Action Network with support from the John D. and Catherine T. MacArthur Foundation and under the leadership of the NCMHJJ to provide juvenile justice staff with critical information on adolescent mental health. The brief presents the origins of the training curriculum, provides an overview of its implementation in pilot states, and shares promising findings from the analysis of this implementation.