The bilingual volume Competențe transversale în educația pentru dezvoltare durabilă și solidaritate internațională/Transversal Competences in Education for Sustainable Development and International Solidarity capitalizes on experiments and data collected within the Erasmus+ Acteurs du Territoire pour une Éducation à la Citoyenneté Mondiale (ACTECIM) project, coordinated by Lyon Academy and held in 2015-2018. This study, conducted in collaboration with researchers from the University of Lyon, the University of Craiova and the University of Turin, proposes a tool to assess the transversal skills associated with education for sustainable development and international solidarity, stating its importance in training tomorrow’s citizens.