Background: Relationship abuse (RA) and sexual assault (SA) are major problems among high school students, and school personnel are an important part of preventing RA and SA among youth. Therefore, we examined the rates and correlates of bystander intentions among school personnel in situations of RA and SA. Methods: School personnel (N = 1150) from 25 high schools in New England completed surveys that assessed their RA and SA knowledge, perceptions of school climate specific to RA and SA, and RA and SA bystander efficacy and bystander intentions. Results: Across each type of bystander behavior measured, the vast majority of school personnel reported intentions to intervene. In the multilevel regression analyses, both proactive and reactive bystander intentions were related to higher levels of RA and SA bystander efficacy and perceptions of a more positive school climate and lower levels of RA and SA barriers to intervene. Conclusions: These data support the utility of school-based interventions that seek to improve school climate and teach school personnel skills that enhance bystander efficacy and reduce bystander barriers in student situations of RA and SA. Although they would need to be evaluated, such interventions could promote positive bystander action among school personnel and untimely contribute to reductions in RA and SA among high school youth.