TST is a comprehensive, phase-based treatment program for children and adolescents who have experienced traumatic events and/or who live in environments with ongoing traumatic stress. TST is designed to address the complicated needs of a trauma system, which is defined as the combination of a traumatized child/adolescent who, when exposed to trauma reminders, has difficulty regulating his/her emotions and behavior and his/her caregiver/system of care who is not able to adequately protect the youth or help him/her to manage this dysregulation. The most common setting in which TST is implemented is for youth in child welfare who can be in birth homes, foster care, residential treatment centers, community-based prevention programs, and programs for unaccompanied refugee minors. There is an emphasis on involvement of the caregiver as being essential to success. TST was developed by Dr. Saxe and Dr. Heidi Ellis at Boston University School of Medicine and Children’s Hospital Boston. The materials are available in Spanish and Korean.