The Complex Trauma Training Consortium (CTTC) is a national-trainer training and workforce development initiative that will establish sustainable local expertise in complex trauma understanding, assessment and treatment within each of the 50 US states, the 5 territories, DC, and the four largest US metropolitan areas, increasing access to child trauma resources and addressing behavioral health disparities in underserved areas with historically limited NCTSN presence. The CTTC will establish a self-sustainable national network comprised of over 200 local state and territory based expert complex trauma trainers across 60 affiliate organizations nationwide, resolving longstanding geographical inequity in distribution of NCTSN resources, particularly to midwestern states, US territories and more rural areas of the country. CTTC trainers will receive intensive trainer-training in a 20 module, 40-hour complex trauma training curriculum comprised covering a comprehensive range of topics that address major knowledge gaps in the field of child and family trauma intervention, including the intersection of complex trauma with adverse life experiences such as historical and ancestral trauma, systemic racism, and substance abuse that pose major public health implications for vulnerable individuals and marginalized communities such as immigrants, LGBTQ+ youth and families, and BIPOC. As part of the CTTC’s implementation-science-driven trainer-training process, trainers will engage in extensive teach-backs and fidelity evaluation with both the curriculum developers and senior technical assistants assigned to each affiliate site. The 200+ trainers in training will each subsequently conduct at least 5 local remote or in-person trainings on the CTTC curriculum offered to multidisciplinary providers working across the social services continuum in each state, territory, district, or metropolitan hub, with emphasis on child mental health clinics, schools, child welfare, juvenile justice, residential treatment centers, foster care programs, and homeless shelters, in addition to hospitals, law enforcement and other first responders, court personnel, clergy, victim advocates, public health, and family/consumer groups. CTTC will achieve a minimum of 1,000 training events over the 5-year cycle of this grant. The CTTC will deliver training to well in excess of 25,000 providers across every US state and territory and will thereby be responsible for trauma-focused workforce development on a national scale. The CTTC is the culmination of the Complex Trauma Treatment Network, a Category II NCTSN Center that between 2009 and 2021 conducted over four dozen regional trauma-informed systems enhancement and evidence-based practice (EBP) dissemination Learning Communities spanning 46 US States and territories in partnership with over 5,000 organizations, delivering over 7,000 hours intensive training and technical assistance to 117,502 multidisciplinary nationwide. The CTTC is a partnership between Adelphi, Alaska Behavioral Health, the Foundation Trust, and U Chicago, and is comprised of a faculty of over two dozen EBP developers, trainers and organizational consultants that is as unparalleled in its subject matter expertise as it is in its racial, cultural, and linguistic diversity