Childhood trauma is associated with psychosocial problems including criminal behaviour. Adverse childhood experiences (ACEs) can lead to neurobiological changes in the brain that compromise emotional and behavioural regulation and increase the risk of mental health disorders and involvement in drugs and crime. This chapter will describe how ACEs can lead to social, emotional, and cognitive impairment, and contribute to the development of delinquent behaviour. Readers will be able to define principles of trauma-informed care (TIC), identify its essential components, and conceptualize cases through a perspective informed by trauma research. The chapter will focus on two general skills: (1) case conceptualization of maladaptive behaviour through the lens of trauma in the context of a youth’s collective experiences, and (2) trauma-informed responding to problematic behaviours in a way that avoids repeating disempowering dynamics in the helping relationship. Using principles promulgated by the US Substance Abuse and Mental Health Services Administration (SAMHSA), readers will be able to apply TIC across a variety of professional roles in the juvenile justice system. Through trauma-informed practices, we can deliver services in a fashion that promotes healing for troubled youth, improves their psychosocial functioning, and disrupts the intergenerational cycle of addiction, crime, and lost potential.