The Alliance for Sustainable Schools (TASS) is a non-profit network of schools working together to help accelerate the transition to a sustainable future. As an agent of change, we harness the collective influence of our members, engage with their students, and partner with innovative organisations in their local communities to catalyse systems change in five focus areas – school food, school buses, school uniforms, school buildings and education for sustainability. In this talk, we will talk about our approach and present case studies of successful systems change demonstrations in schools around the world.