PROJECT SUMMARY Mental health problems have increased substantially in the last decade, and Hispanic youths’ experiences of racism and marginalization increases risk for internalizing and externalizing symptoms. Effective implementation of evidence-based interventions is critical to reduce mental health disparities among ethnic minority populations and to scale up for dissemination. Cultural adaptation has improved parenting practices and youth outcomes beyond the original evidence-based parenting interventions and has the potential to support cultural socialization, which is associated with mental health among Hispanic youth. We have developed Family Check-Up Online (FCU Online), a mobile, web-based application designed to reduce internalizing and externalizing behaviors (e.g., depression, anxiety, child problem behavior). The goals of this Phase 1 study are to culturally adapt the FCU Online for Hispanic parents and to test the feasibility, acceptability, and commercial potential of the adapted intervention. A community engaged approach will be employed to identify strategies to improve access to and uptake of the intervention, leveraging community and cultural resiliency-promoting assets. Promotores de salud, Spanish-speaking community health workers will provide feedback and pilot delivery the program to meet the needs of Latinx families from diverse backgrounds. To reach the goals of the study, the following aims will guide this research. In Aim 1, interviews with parents and community leaders, including promotores de salud, will inform the ecological, cultural adaptation of the FCU Online modules and the online portal for promotores de salud. In Aim 2, the online version of the intervention will be adapted using iterative Plan-Do-Study-Act cycles to get usability feedback from parents and promotores de salud, consistent with best practices designed to adapt interventions in community settings. In Aim 3, using mixed methods, researchers will assess feasibility, accessibility, and commercial potential of the adapted FCU Online. The team will recruit 10 Hispanic families and 5 promotores de salud to participate in a pilot trial. Feasibility and accessibility will be assessed according to quantitative benchmarks, including technology usage data, a telehealth usability survey, and a consumer satisfaction scale. Qualitative feedback will assess the barriers and facilitators of using the adapted FCU Online. Qualitative and quantitative data will be integrated for analysis. Findings from this study will inform a future Phase 2 randomized controlled trial to test effectiveness in a real world setting to scale up dissemination of the adapted FCU Online among Spanish speakers. This research has potential to reduce lifetime risk for depression, anxiety, and externalizing behaviors among Hispanic youth by improving parenting practices and supporting cultural socialization.