The article explores the phenomenon of nationalism in general and its Eastern Christian nuances in particular. It describes two major theories of nationalism: modernist and primordial. It also distinguishes between two stages of nationalism: emancipatory and oppressive. The former is healthier than the latter. The article focuses on the Orthodox editions of nationalism, which seemingly coheres with the traditional structure of local churches. In the Orthodox world, national particularity combined with ecclesial locality, can be either ethnic or civilizational. In the former case, it enhances a homogeneous national identity of the Balkan style. The latter case is an Orthodox neo-imperialism, which is incompatible with nation-building on the basis of one ethnicity. Their incompatibility often leads to conflicts and even wars.