Social cleavages and their political projections are key systemic elements in the evolutionary transformations of modern societies. Cleavage theory seeks to reflect the ambiguous and dynamic realities of contemporary divisions, but concepts and notions describing them often remain unclear. An overview of the mainstream theoretical and methodological approaches to assessing social and political divisions in contemporary societies indicates three key analytical standpoints: a) classical theory of social cleavages and their political projections (following Stein Rokkan and Seymour Martin Lipset); b) the politicization of new social divisions and of their potential transformation into competitive resources for promoting political projects; and c) political divides as drivers of social development. A correlation of these approaches can contribute to promoting a complex methodology of assessing political transformations in a rapidly changing contemporary world order. Economic and social inequality, cultural divides, and contentious politics are important indicators of growing divisions, alongside an ardent public discussion and a consistent research agenda on cultural and socio-political polarization. The authors consider institutionalized political divisions between identity groups (in the logic of Arend Lipjhart) as one of the possible characteristics (but not the only one) of divided societies, and argue for a wider approach to this concept. Growing cleavages of different natures are integral parts of contemporary social dynamics, but not all are politically relevant: politicizing cleavages is an inherent characteristic of “divided societies”, and criteria for their assessment are proposed. These criteria are applicable in the framework of both territorially localized (the nation state) and extraterritorial (non-state) communities. A cognitive map of cleavages and their political projections depicts the current state of the research field and offers insights for updating the research agenda.