Applying Organizational Routines Theory this study aims to better understand the role of the teamwork routine as a central link between leadership and school effectiveness. Looking for the internal structure of the routine, we employed a multi-case study approaches in five successful schools and four coasting schools. The findings show that while the routine's name is the same across all schools, the performance and alignment of the routine's internal aspects explain the differences. We conclude that the more the principal demands accountability and backs the department head, the weekly meetings are more effective, and teachers' competency is higher. Theoretical and practical implications are discussed.