This chapter provides an orientation to the critical issues, history, trends, policies, programs, and intervention strategies of the juvenile justice system. It reviews the types, functions, and legal responsibilities of the various juvenile justice agencies and institutions. The chapter describes the case flow within the juvenile justice system. It also discusses systems of care in juvenile justice, and specialized assessment and treatment issues with adolescents, including sexually abusive youth. It explores the foundation and groundwork for the study of juvenile delinquency and juvenile justice system while delineating the legal definitions of juvenile status offenses and juvenile delinquency, examining the nine steps in the juvenile justice case-flow process. The chapter also gives attention to systems of care, the link between trauma and delinquency, as well as the assessment and treatment considerations for forensic social workers when addressing the specialized needs of juveniles in the justice system.