This article analyzes the structural and institutional conditions related to the presence of autonomist and secessionist political parties. Since not every multinational or plurinational democracy presents demands of secession or redefinition of the political community in terms of the demos, the main hypothesis here is that there exists a combination of structural factors that explains the phenomenon. Adopting a non-probabilistic approach (csQCA), this article finds that regional concentration together with legacies of self-government plays a necessary role to explain the emergence of parties that articulate minorities’ territorial demands in post-communist countries.