Bystander interventions have been highlighted as promising strategies to reduce sexual violence and sexual harassment, yet their effectiveness for sexual minority youth remains largely unexamined in high schools' populations. This rigorous cluster randomized control trial addresses this gap by evaluating intervention effectiveness among sexual majority and minority students known be to at increased risk of sexual violence. Kentucky high schools were randomized to intervention or control conditions. In intervention schools, educators provided school-wide Green Dot presentations (phase 1) and intensive bystander training to student popular opinion leaders (phase 2). Each spring from 2010 to 2014, students attending 26 high schools completed anonymous surveys about violence acceptance and violent events. An analytic sample of 74,836 surveys with no missing data over the 5 years was available. Sexual violence acceptance scores declined significantly over time in intervention versus control schools among all but sexual minority males. This intervention was also associated with reductions in both perpetration and victimization of sexual violence, sexual harassment, and physical dating violence among sexual majority yet not sexual minority youth. Both sexual minority and majority youth experienced reductions in stalking victimization and perpetration associated with the intervention. In this large cluster randomized controlled trial, the bystander intervention appears to work best to reduce violence for sexual majority youth. Bystander programs may benefit from explicitly engaging sexual minority youth in intervention efforts or adapting intervention programs to include attitudes that shape the experience of sexual minority high school youth (e.g., homophobic teasing, homonegativity).
Keywords: Bystander intervention; Sexual minority; Violence acceptance.