PROJECT SUMMARY/ABSTRACT Maternal depression disproportionally affects low-income, ethnic minority mothers of young children, and can lead to poor child outcomes in a variety of domains, including parent-child relationship quality, child behavior problems, and school readiness skills. Although intervention researchers have developed several efficacious treatments for depression over the past several decades, utilization of these treatments among poor minority mothers in community settings remains limited. Two-generation programs in Head Start offer a unique opportunity to provide evidence-based parent support and treatment services for low-income mothers that may have difficulty accessing and utilizing treatment. However, research from implementation science shows that intervention efficacy is not sufficient to ensure the successful implementation of evidence-based treatments (EBTs) in community-based settings. Instead, it is critical to assess the specific needs and capacity of clients, practitioners, agency leadership, and funders in creating and implementing EBTs for particular populations and settings. In addition, research has not yet identified the relative importance of these factors in implementing parental support and treatment services in publicly funded child-serving organizations, particularly for minority mothers facing multiple stressors. Therefore, the proposed study will utilize a mixed-methods approach to evaluate how political, organizational, and person-level factors positively or negatively influenced the implementation effectiveness of an EBT for depression (IPT-Group) in a Head Start setting, and will identify causal relationships between these factors. In addition, the study will provide recommendations about how to further adapt IPT-Group and other evidence-based mental health treatments in order to more effectively meet the needs of low-income, ethnic minority mothers in Head Start. During the first phase of the proposed study, qualitative data will be gathered from mothers and agency staff through in-depth interviews to examine implementation effectiveness and to identify factors predicting implementation success or failure. In the second phase, quantitative intervention and administrative data from the ?Healthy Moms, Healthy Kids? parent study will be used to evaluate the implementation effectiveness across several domains. Subsequently, the research team will use mixed methods approaches to identify potential causal mechanisms explaining implementation success and develop ideas for future adaptation. Taken together, these findings will be used to develop recommendations for researchers, practitioners, and policy-makers regarding how to further adapt IPT-Group and other mental health treatments for use in Head Start and similar settings in order to best address the needs of low-income minority mothers experiencing depression and their children. As part of the proposed study, the PI will develop expertise in implementation science theories and frameworks, complete training in advanced qualitative and mixed methods, build connections with other researchers in the field of young children and families, and develop a deeper understanding of how to intervene with her population of interest.