This study examined the role of welfare services in the participative citizenship of young people under 30 years of age outside the labour market. Thematic content analysis of the government’s white papers regarding participation policies, as well as participatory action research projects in two Finnish towns, were used to identify factors that enable or hinder participation for this group of service users. The paradigm of participation was critically examined with reference to the theoretical framework of Max Horkheimer and Theodor Adorno’s “dialectic of Enlightenment”, which proposes the parallel existence of the promise and the deception of Enlightenment. The results indicated that user participation holds the potential to promote democratization, consolidation, and qualitative improvements in services, especially by valuing experience-based knowledge and enabling the growing political citizenship of young people. However, the promises of the paradigm of participation can turn toward deception when applied as a managerialistic workfare instrument to control young people’s behaviour and can even deepen marginalization by focusing only on their absence from workforce participation. The ambivalent role of social sciences and social work as agencies of Enlightenment in developing participation technologies is also discussed.