EU strategic documents emphasize the need to support youth citizenship and involvement in policy making and research and foster youth social inclusion in general. However, these aims are not achieved yet, in particular, considering youth from socially vulnerable groups. There is a lack of knowledge of what are innovative ways to facilitate social inclusion of youth. YouCount project seeks to show that Y-CSS might be an effective and sustainable way to achieve these ambitions and proposes 10 recommendations for decision-makers in the European Union on co-creating youth-friendly societies through Citizen Social Science.