The ongoing process of globalization and regionalization as well as the reconciliation between South and North Koreas make it imperative to rethink the debates on socio-cultural integration. Until recently socio-cultural integration in the modem societies has been discussed within the boundaries of nation-states. Whether the cultural and social citizenship can be established and secured has been hotly debated because socio-cultural integration within a nation-state contains the possibilities of difference, discrimination, inequality, and conflict. Moreover, the ongoing process of globalization and regionalization has promoted not only the divergence of identities within a nation-state, but also the new identities beyond nation-states. In this context, socio-cultural integration at the level of nation-states appears more and more difficult. Therefore, while the issue of how to extend the cultural and social citizenship within nation-states remains crucial, it is necessary to consider the emerging concept of "multi-layered" socio-cultural integration. In order to discuss socio-cultural integration in Korean peninsular, in which in the nationalist perspectives the modern nation-state formation is not still incomplete (i.e., the discordance of the boundary of nation and state), the powers and perils of nationalism should be more emphasized. The strong nationalism(s) of both South and North Koreas could be operated as a strong ideology of integration, while also containing a potential force that suppresses diversities within civil societies. In this regard, securing the social and cultural citizenship in institutional arenas is one of the most crucial means for the socio-cultural integration between South and North Koreas as well as for reducing the dangers of nationalism.