Purpose: Organizational citizenship behavior (OCB) has received much attention in the past decade as scholars have recognized its significant impact on the success of organizations. The current study seeks to enrich our understanding of citizenship behavior in the school setting by identifying the main factors that may enhance this behavior among teachers. Design/methodology/approach: Specifically, the paper examines the direct effect of teachers' participation in decision making (PDM) on their OCB, and the impact of teacher empowerment, as a mediating variable, on this relationship. Data were collected from 983 teachers in 25 junior and 27 senior high schools in Israel. Findings: Hierarchical regression analyses revealed that teacher empowerment played an important role in mediating the relationship between teachers' PDM and OCB. Involvement in decision-making processes induces teachers to take on new roles and have a more direct impact on school life, which in turn might lead them to invest extra efforts in achieving school objectives. Principals and school administrators should acknowledge the importance of empowerment to teachers, and involve teachers in decision making within the managerial arena too. Originality/value: The results of the study contribute to our understanding of the way PDM and OCB interact in schools, and the importance of teachers' sense of empowerment in explaining this relationship. Future research should further investigate the organizational citizenship within schools as little research has been conducted to date. (Contains 3 tables.)