Detailed Description: The commercial sexual exploitation of children (CSEC) is a public health crisis in the U.S.1-4 Research has documented risk and protective factors across the social ecology for CSEC,2,5-8 that many perpetrators (traffickers, clients, recruiters) of CSEC are peers (e.g., romantic partners) 9-11 and adolescents report opportunities to intervene in situations of peer victimization (although not necessarily specific to CSEC).12-14 Prevention efforts with adolescents that seek to (1) reduce risk for CSEC perpetration; (2) reduce risk for CSEC victimization; and (3) increase positive bystander intervention in situations of CSEC is urgently needed. Thus, the goal of this multi-stakeholder collaboration-that includes researchers, educators, practitioners, and youth-is to conduct both a process and rigorous outcome evaluation of The Set Me Free Project's© (SMFP) READY to Stand (RTS)© curriculum-with an eye toward widespread dissemination to other U.S. communities, if deemed effective. This project is responsive to Research Priority Area 4 (preventing CSEC as a form of CSA) of RFA-CE-22-003. The implementation site includes eight high schools in Des Moines Public Schools (DMPS); students (naïve to the RTS curriculum) are largely racial/ethnic minority (65%) and low-income (76%). DMPS leadership have expressed a growing concern about the CSEC in their district and are eager to partner with researchers to rigorously evaluate the RTS curriculum. The RTS curriculum includes four, 45-minute modules implemented to high school students in mixed gender groups of \~25 students and provides students with psychoeducation on CSEC, healthy relationship skills training, identification of safe people/resources, and programming components to enhance valuing of self and others. As part of the proposed project, the RTS curriculum will be enhanced with two additional 45-minute modules on bystander intervention training in situations of CSEC and shifting school norms to be intolerant of all forms of violence, including CSEC. Additionally, school personnel participate in an enhanced (from 90 minutes to 120 minutes) training to equip them with skills to effectively respond to students' disclosures of CSEC and to reinforce programming messages. The RTS curriculum may also reduce other forms of violence such as teen dating violence (TDV) given it addresses risk and protective factors for multiple forms of violence. Despite its potential for reducing CSEC, the RTS curriculum has never been evaluated. Specific Aims are as follows: Refinement and Planning Phase (Component A): Convene a Research Advisory Board (RAB) that includes researchers, practitioners, educators, caregivers, and youth who will provide input on all research components of the project (Aim 1a). Conduct focus groups with students (n=80) and school personnel (n=60) to inform the refinement of the RTS curriculum and research procedures for Component B (Aim 1b). Enhance the existing RTS program manual and create a training manual to ensure consistent implementation, produce training manuals for use in subsequent clinical trials and dissemination, and develop fidelity measures (Aim 1c). Develop via cognitive interviews (n=20 youth, n=10 school personnel) and surveys (n=878) with students valid, reliable, and developmentally appropriate measures of CSEC perpetration, CSEC victimization, and CSEC bystander opportunity/action to be used in subsequent research, including Component B (Aim 1d). Conduct an open pilot trial of the RTS curriculum in one of the five traditional high schools and one of the three alternative schools in DMPS with students (n=878) and school personnel (n=78) to gain experience with the recruitment and assessment procedures and administration of the intervention; assess acceptability and safety of the research protocols; document initial trends, effect sizes, and CSEC incidence rates; and refine the intervention and research procedures in preparation for Component B (Aim 1e). Apply for additional funding under Component B and disseminate findings to diverse audiences in collaboration with the RAB (Aim 1f). All procedures for Component B will be ready for implementation by the end of Component A funding. Rigorous Evaluation Phase (Component B): Conduct a quasi-experimental study in which four traditional high schools in DMPS and two alternative high schools (not including the two high schools that participated in Component A) are demographically matched and randomly assigned to treatment or wait-list control conditions. Students (n=7,241) will complete baseline and 6-, 12-, and 18-month follow-up surveys to test the hypothesis that participation in the RTS program will lead to reductions in CSEC perpetration (primary outcome), as well as reductions in CSEC victimization and TDV and sexual violence victimization and perpetration and increases in bystander intervention in CSEC situations compared to participants in the waitlist control condition (secondary outcomes) (Aim 2a). We will assess mediators and demographic moderators of program impact (Aim 2b). Document via program observations of student and school personnel programming (Aim 2c), post-session surveys (n=7,241 students; n=396 school personnel) (Aim 2d), and post-program implementation key informant and stakeholder interviews (n=40: program facilitators \[n=10\], students \[n=20\], school personnel \[n=10\]) (Aim 2e) variations in implementation, unanticipated challenges, lessons learned, and perceptions of program impact. Determine costs associated with the program implementation (both student and school personnel programming) to inform future economic evaluation of the RTS curriculum (Aim 2f). Refine and assess validity and reliability of school personnel's' CSEC prevention related knowledge, attitudes, and skills (Aim 1g). Examine the preliminary impact of the RTS school personnel training curriculum on CSEC prevention related knowledge, attitudes, and skills as well as acceptability and perceptions of impact (Aim 1h).