PROJECT SUMMARY/ABSTRACT Human immunodeficiency virus (HIV) and sexually transmitted infections (STIs) substantially burden youth 14– 18 years of age in the United States (US). Heightened risk for HIV/STI acquisition among adolescents is due in part to inadequate sexual health education (i.e., “sex ed”) in the US. Some youth lack access to accurate and relevant information about sex and HIV/STI prevention and turn to sexually explicit media (SEM) to learn how to have sex. Mainstream SEM often depicts high-risk sex including condomless sex and aggressive sex with no consent negotiation. Consequently, the 2020 version of the National Sex Education Standards for K-12 recommends that US schools educate students about SEM. Despite this, no evidence-based SEM education programs exist. The Co-PIs of this project have tested SEM education programs for youth, but their existing programs were either designed exclusively for sexual minority male youth, or focused on SEM but without HIV/STI education built in. The present project will be informed by elements of both prior SEM education programs and produce a new, theory-based, online SEM education module for all high school youth to be used as part of school-based sex ed. The new online module will focus on the unrealistic sex depicted in SEM and HIV/STI prevention and incorporate education about sexual consent and dating violence. Specifically, our Aim 1 formative research and intervention development process will: (1) Include in-depth formative interviews with the intended end-users and administrators of the SEM education, including 40 youth (ages 14-18), 10 school- based health educators, and 10 school administrators recruited from our partner school systems; (2) Use interview results to guide selection of content elements from our prior SEM education programs and tailor the content for the new population and setting; and (3) Refine module content choices and visuals using a Delphi process with 5 nationally-recognized sex ed and SEM experts. For Aim 2, we will pilot test the feasibility and acceptability of the online SEM module with a sample of 14-18 year old youth (N=40) recruited from our partner school systems. Youth will self-administer the SEM module at home and complete pre- and post-test surveys. A random subset of 20 will also be interviewed about intervention content and process. Primary outcomes are related to feasibility and acceptability including (a) user satisfaction; (b) intervention retention; and (c) research retention. We will also generate preliminary estimates of efficacy by comparing pre- and post- test scores on behavioral outcomes (condom use, HIV/STI testing, dating violence), behavioral intention outcomes (intentions to use condoms), and knowledge outcomes (HIV/STI-related knowledge, SEM-related knowledge). Consistent with stated priorities in the NIH Strategic Plan for HIV-Related Research, the proposed research constitutes a new and innovative HIV prevention approach within a s...