This article critically reviews three of the most significant debates in the sociology of nations and nationalism over the past 50 years: (1) the problem of methodological nationalism on the main features of nation-states; (2) the tension between primordialism and modernism in understanding the historicity of nations; and (3) the politics of nationalism between universalism and particularism. These three debates help us clarify some key theses in our long-term understanding of nations and nationalism: processes of nation and nation-state formation are not opposed to but compatible with the rise of globalisation and non-state forms of governance; the question ‘when is a nation?’ combines modern and pre-modern dimensions; the politics of nationalism is neither unfailingly democratic nor exclusively regressive. A key paradox that unfolds is that all nations invest heavily in the production and reproduction of their own exceptionalism.