Child participation, that is, the inclusion of children and adolescents in decision-making, is one of the great challenges of consolidated democratic societies. The social representations under which girls, boys and adolescents are considered to be ‘future citizens’, ‘incapable’ or ‘semi-citizens’ must be overcome in order to be recognized as active citizens in the present and the here of our society. This project aims to approach the components and strategies that enable the promotion of children’s participation. It has been awarded in the 2018 call “Research Challenges: A Way to Make Europe”, and funded, from 2019 to 2022, by the Ministry of Science and Innovation and the European Regional Development Fund (European Union). It is developed by the ChildCity research team that includes researchers from the University of Barcelona, the National University of Distance Education, the University of Seville and the University of A Coruña. This team cannot do without the voice of its true protagonists: children, children and adolescents, technical figures and elected officials at the local level with direct involvement in the participation policies of children and adolescents. It also has the invaluable support of the International Association of Educating Cities (IAEC) and UNICEF Child-Friendly Cities (CAI.UNICEF), both consolidated and recognized networks for their contributions in this field and with an impact on Spanish territory. .