This guide explores Collective Teacher Efficacy (CTE), a powerful concept that centres on the shared belief among educators in their collective ability to positively impact students’ learning. Recognized as a critical factor in fostering a collaborative school environment, CTE empowers collective action within the school community, creating a united front to address challenges and pursue common goals. This unified approach doesn’t just benefit students—it significantly influences teachers and school administrators across various domains, such as improving work conditions, boosting job satisfaction, and encouraging effective teaching behaviours. Research shows that CTE can lead to improved student outcomes, making it a key driver in school-wide transformation efforts. Understanding and building CTE is essential for educators who aim to create meaningful, lasting change in their schools.