The authors of this article, Silvia Diazgranados Ferráns and Robert Selman, use an emergent framework to explore how the rules of the school culture at different perceived school climates affect early adolescents' decisions to upstand, bystand, or join the perpetrators when they witness peer aggression and bullying. Through a grounded theory approach, they revisit interview data from twenty-three eighth graders in four middle schools, with the aim of building on previous research and refining their theoretical framework to guide future research on bullying. The authors identify four school-level indicators that are salient in students' perceptions of their school climate--safety, order, care, and empowerment--and examine how these indicators combine to configure three types of perceived school climates--negligent, authoritarian, and cohesive. They explore how these perceived school climates influence adolescents' choice of strategy when they witness bullying in school and document a set of student recommendations about what schools can do to prevent bullying.