This report discusses the intersection between system-involved youth and runaway and homeless youth. It cites data from interviews with 656 runaway and homeless youth (ages 14 to 21) in 11 cities that show nearly 78 percent of the participants had at least one interaction with law enforcement. In addition, 7 percent of survey participants directly attributed their first homelessness experience with exiting jail or prison. In Part I of the report, the authors describe each of the 10 Principles of Change developed by the Coalition for Juvenile Justice in collaboration with the National Network for Youth and the National League of Cities Institute for Youth, Education, and Families. The principles provide a roadmap for communities to help young people avoid experiencing juvenile justice system involvement or youth homelessness. In Part II, the report gives specific resources and examples related to each Principle of Change. Appendix I outlines a case study of Davidson County, Tennessee, as a juvenile court system working to decriminalize and address youth homelessness. Appendix II describes state-level efforts in Maryland, South Carolina, and Vermont that focus on homelessness among system-involved youth.