Bullying, which is prevalent in schools and can have widespread adverse consequences for all involved, consists of much more than the two roles of bully and victims; bullying involves the whole school. It is best viewed as a behavioral pattern that emerges from social, physical, institutional, and community environments as well as the individual characteristics of the youth involved. Various environmental factors can have a powerful influence on school bullying by either encouraging or maintaining its occurrence. Researchers have documented several important environmental factors related to bullying behavior, including teachers' implementation of bullying prevention lessons, teacher coaching of students involved in bullying, teacher beliefs about bullying, and victim and peer responses to bullying. Based on existing theory and research, this article focuses on a "protective peer ecology" as the key component for preventing and intervening in bullying at school. A "protective peer ecology" refers to the "aspects of children's interactions with one another that serve as a shield against internal or external sources of stress." In support of the concept of protective peer ecology, research has convincingly shown that positive peer affiliations (having a friend, number of friendships, and peer acceptance) are significantly related to being bullied less. Based on the research literature, this article suggests some innovative school programs that promote a friendly, prosocial school environment that encourages helping and advocacy among students. The proposed basic model for bullying prevention and intervention consists of measures designed to teach and reinforce school-wide support for positive behaviors, instruction in positive peer interactions, and the cultivation of protective peer behaviors. 1 figure and 65 references