Since the late 1970s, ever-increasing immigration flows to Portugal have led to the state having to create programs aimed at the insertion of these individuals into Portuguese society. Consequently, as part of these measures, since the early 1990s, significant steps have equally been taken towards establishing policies and institutional instruments that encourage the participation of immigrants at both the national and local levels. Going hand-in-hand with these initiatives, the settlement of immigrant communities in Portugal has also led to foreign groups taking important steps towards collective mobilization, primarily in the form of associations, in defense of their own causes. These points considered, this chapter sets out to: (1) provide insight into the complex relations between immigrant mobilization opportunities and the set of legal and institutional frameworks developed by local and national government authorities targeted towards the incorporation of immigrants; and (2) analyze the opportunities made available to immigrant-representing organizations and the lobbying tactics adapted by these institutions when it comes to decision-making and policy issues.