Mentored patient-oriented research that applies a social determinants of health lens to promote optimal developmental and behavioral health in primary care - School entry is an important developmental stage during the life course. Developmental and behavioral health at this stage, which includes cognitive, communication, and social-emotional development, are powerful predictors of later educational attainment, a social determinant of health (SDOH), and long-term health and wellbeing. Pediatric professionals in primary care have near-universal access to young children, frequent contact with their families, and opportunities to build trusted caregiver-clinician relationships making primary care the right place to support optimal developmental and behavioral health. Neuroplasticity makes early childhood the right time to intervene since developmental and behavioral health promotion interventions can have large effects during this developmental stage. However, to date, healthcare interventions have largely missed the opportunity to support optimal developmental and behavioral health in primary care settings. Primary care literacy promotion, a pediatric standard of care supported by the American Academy of Pediatrics and the National Association of Pediatric Nurse Practitioners, represents an exception and is an exemplar prevention and health promotion intervention that can promote optimal developmental and behavioral health at scale. However, prior work by our team and others points to inconsistent implementation that threatens to dilute its impact. Patient-oriented research that applies SDOH and prevention and health promotion lenses is needed to help address this gap. The overall objectives of this K24 application are to provide Dr. Manuel E. Jimenez with mentorship-focused protected time to: (1) augment his research capabilities building on his funded patient-oriented research program that uses community-engaged research and implementation science to address SDOH in primary care, and (2) mentor the next generation of interprofessional clinician investigators and enhance their capabilities to apply SDOH and prevention and health promotion lenses on patient-oriented research. To achieve these objective Dr Jimenez proposes the following specific aims: (1) To examine which literacy promotion components are most important and why from the perspective of literacy promotion experts and caregivers, (2) To identify consensus on literacy promotion core components among intervention experts and other key partners including families, and (3) to develop an intervention that supports tailored literacy promotion implementation strategies and test the feasibility of the intervention in community health centers. The application addresses multiple NINR priority areas and will help train the next generation of clinician scientists in SDOH, community health, and intervention research that positively impacts practice and policy to help address the pressing health challenges facing the nation.