The prevalence of mental health problems among children (ages 0-21) in the United States remains unacceptably high and, post-COVID-19, is expected to increase dramatically. Decades of psychological knowledge about effective treatments should inform the delivery of better services. Dissemination and implementation (D&I) science has been heralded as a solution to the persistent problem of poor quality services and has, to some extent, improved our understanding of the contexts of delivery systems that implement effective practices. However, there are few studies demonstrating clear, population-level impacts of psychological interventions on children. Momentum is growing among communities, cities, states, and some federal agencies to build "health in all policies" to address broad familial, social, and economic factors known to affect children's healthy development and mental health. These health policy initiatives offer a rare opportunity to repurpose D&I science, shifting it from a primary focus on evidence-based practice implementation, to a focus on policy development and implementation to support child and family health and well-being. This shift is critical as states develop policy responses to address the health and mental health impacts of the COVID-19 pandemic on already-vulnerable families. We provide a typology for building research on D&I and children's mental health policy. (PsycInfo Database Record (c) 2020 APA, all rights reserved).