Incidents of school violence have prompted calls for school communities to create environments that encourage student bystanders to act responsibly and proactively when they confront a range of violent incidents, from bullying and fights to weapon carrying and other serious threats to school safety. It is not always clear, however, what bystanders would--or should--do when faced with violent or potentially violent situations. This article describes findings from focus groups conducted with 54 middle school students and 97 staff in an urban, predominantly African American school district with relatively high levels of community violence. Discussions addressed bystander norms, attitudes, and behaviors, and identified barriers that prevent youth as well as adult bystanders from taking positive action. Findings inform violence prevention strategies for building consensus and supporting positive bystander responses. (Contains 1 table.)