Previous research highlighted the underrepresentation of immigrants in receiving societies’ political system. Furthermore in countries with authoritarian legacies a tendency for civic apathy and weak parties was identified. Under such circumstances, what are the chances for immigrants’ political claims within the political opportunity structure (POS)? What role do individuals and groups play – their agency – in propelling immigrants’ political claims? Taking Portugal as a case study, this article analyses how immigrants’ political inclusion is influenced by access to political rights, the party system, and the citizenship regime, envisaging a comprehensive view upon the macro-structure that creates the conditions for such inclusion. The POS’ analytical role is discussed to understand immigrants’ political mobilization and involvement with political parties. Additionally, acknowledging that political contexts can be appropriated differently by actors, we consider the weight of perceptions (and its mismatches with the objective POS), by analysing the discursive environment in which political strategies occur.