This study examines how non-profit organizations that engage in advocacy maintain their legitimacy in the eyes of their target group of vulnerable citizens. The existing body of literature shows that these organizations are challenged in their pursuit of citizen legitimacy, defined as the extent to which their constituent target group perceives the organization as justified, accepted and appropriate. This paper draws on the results of qualitative research in government-funded non-profit community work organizations that develop advocacy activities to influence policymakers. We interviewed community workers and their target group of citizens in four community centers in Flanders, the northern region of Belgium. We show that community workers engage in practices to enhance both the input and throughput legitimacy of their advocacy activities. More specifically, they construct safe spaces through informality, ensure proximity by taking care of individual needs, and collectivize individual needs.