Project Summary National Survey on Drug Use and Health (NSDUH) data show that past-year prescription opioid use (i.e., pain relievers) in 2019 for older adolescents and young adults (AYAs) was: 19.7% (ages 16-17), 24.8% (ages 18-25), and 28.2% (ages 26-29), whereas past-year opioid misuse (prescription+illicit) rates were: 3.4% (ages 16-17), 5.3% (ages 18-25), and 5.8% (ages 26-29). Thus, use of opioids by AYAs (ages 16-30) is a public health concern requiring scalable and sustainable strategies to prevent opioid misuse and opioid use disorders (OUDs), and prevention approaches implemented in health systems have the potential to alter risk trajectories. In this supplement, “opioid” misuse includes prescription opioids (without a prescription, more than prescribed, or for reasons other than prescribed) and use of illicit opioids (e.g., heroin, fentanyl analogs). This supplement request is directly responsive to NS-21-025 by requesting support to increase participant diversity and inclusion in our ongoing HEAL Prevention Initiative-funded randomized controlled trial (RCT) to technology-driven prevention interventions. The NSDUH data show that past-year prescription opioid use and misuse rates are concerning among Black/African American AYAs. Further, Black/African Americans are historically under-represented in prevention research and clinical trials, but, given racial disparities in OUD treatment access, it is critical to fully engage these populations. Thus, we propose two aims related to our RCT: 1) Increase outreach to enhance inclusion of AYAs who identify as Black/African American, permitting meaningful analyses of moderators (enrolling ~N = 110 additional AYAs), and 2) Enhance inclusion in our implementation aim by conducting in-depth interviews (IDIs) with Black/African American participants after follow-up (N =20) to identify: a) barriers/facilitators to future implementation of interventions for this sub- population, and b) aspects of the recruitment/intervention delivery that were perceived by participants as engaging and/or helpful or recommendations for modifications to increase appeal and helpfulness. Thus, greater involvement of Black/African American AYAs in this RCT will enhance the generalizability and cultural relevance of the interventions for planned dissemination. Qualitative methods will inform vignettes of patient journeys that characterize their experiences (from the Emergency Department touchpoint through intervention delivery) and outcomes for dissemination at HEAL meetings and in our implementation toolkit. By supplementing current efforts, we are poised to have a greater impact on the problem of opioid misuse and OUD through enhanced inclusion of under-represented individuals. Our use of electronic health record- facilitated recruitment and IDIs to inform our implementation toolkit are key innovations that support future integration of our technology-driven prevention interventions in healthcare systems.