The UNESCO Associated Schools Project Network (ASPnet) in Action: Global Citizens for Sustainable Development student guide aims to introduce secondary school students to Global Citizenship Education (GCED) and Education for Sustainable Development (ESD) and provide them with ideas and activities to contribute proactively to a more peaceful and sustainable world. The guide draws on the discussions and activities of almost 1,100 participants from 104 countries, including ASPnet National Coordinators, school principals, teachers, students and experts who contributed to the ASPnet Online Collaborative Platform: Global Citizens Connected for Sustainable Development in 2014 and 2015 [http://en.unesco.org/aspnet/globalcitizens]. You will find in this student guide: An overview of what it means to be a global citizen and of how you can contribute to sustainable development. Ideas for getting active yourself, as part of your home, school, community, country and globally. Selected activities on GCED and ESD from ASPnet schools around the world.