Abstract Serious stress-related public health concerns exist for today’s Latin American-origin youth. Chronic and/or severe exposure to adversity can elevate stress processes in the family (e.g., increased maternal depression) and manifest through youth’s behavioral health (e.g., unhealthy diet), and biology (e.g., flatter diurnal slopes of daily cortisol output). These stress processes can increase mental health and chronic disease risks and limit social mobility for Latino/a youth making the consequential transition to adulthood. We propose major expansions to Caminos, an NICHD-funded study collecting 8 time points of data at 6-month lags (2018-2021) for a diverse sample of 547 Latin American-origin adolescents (88% U.S. born) and mothers (80% foreign born) in suburban Atlanta, GA. The proposed study will add five time points of annual data, extending current measures into the transition to adulthood and assessing hair and salivary cortisol indicating chronic and acute stress, waist circumference, and survey reports of chronic disease risk and social mobility. The 13 time points of data (2018 to 2026) will trace the onset of behaviors from as early as age 11 and occurring during a time of important societal changes. We will use state-of-the-art methods to multiply impute intentionally and unintentionally missing data for a cohort of mother-child dyads with high retention in the ongoing study. Guided by family stress models and contextual-developmental theory, cross-lagged path models and latent growth mixture models will test the hypothesis that family, biological, and behavioral health stress processes mediate associations between adversities (e.g., low interpersonal support) and youth’s mental health risks (internalizing and externalizing symptoms, substance use), chronic disease risks (e.g., asthma, diabetes), and social mobility (e.g., educational attainment). Using tests of moderated mediation, we will identify community-, family-, and individual-level protective factors that mitigate impacts of stress on youth outcomes. Sex as a biological variable will be examined as a key modifier. Unique from other national and cohort studies, the proposed research will identify how accumulated adversities shape Latin American-origin youth’s health outcomes and social mobility over time. In addition, the proposed study is uniquely situated to assess factors within and outside of the residential neighborhood, namely, within mothers’ daily activity spaces. Elevating study impacts, findings will inform preventive interventions and programs that can improve health for youth as they prepare for adulthood.