Current societal conflicts are characterized by identity struggles and discontent concerning globalization and modernization. While the literature identifies several psychological determinants of this discontent, systematic measurement approaches based on well-defined constructs are rare. Here, we present the development and validation of the Perceived Societal Marginalization (PSM) scale, which aims to assess individual differences in people’s subjective perceptions of the insignificance and lack of recognition of their own social groups in the economy, culture, and politics. We first provide a definition of PSM and a conceptual analysis of its components based on (a) a top-down review of relevant psychological, sociological and political science theories and (b) a bottom-up approach involving semi-structured group interviews with various German citizen associations followed by a qualitative content analysis. We then present the results of a psychometric validation of the PSM scale (factor structure, reliability) based on three large online surveys with heterogeneous samples (total N = 2,566) and explore sociodemographic, personality, and attitudinal correlates. The discussion focuses on applications of the PSM scale, that is, the role of PSM in explaining societal cleavages as well as threat perceptions towards and rejection of cultural, ethnic, and religious minorities.