Abstract: In diversity studies, categories of difference are seen as building blocks. Critical organisational scholars emphasise the need to move from fixed conceptualisations of identity towards a more flexible, intersectional, multi-layered, and context-sensitive understanding of social difference and organisational inequality. This critique also involves shifting from a social psychology lens to a sociologically-oriented and historically-informed perspective. The elusive and multi-dimensional nature of Jewish identity offers a unique opportunity to explore those complexities around organisations and social difference. Jewish difference seems to disrupt diversity scholarship and practice, problematising ideas of whiteness and otherness, dominance and marginality, diaspora and homeland. Bridging the gap between EDI and Jewishness—and between management and organisation studies and Jewish studies—is of theoretical, practical, and political importance. The research study presented in this thesis examines the construction of diversity and difference in Jewish nonprofit organisations in the UK. It is positioned at the intersection of three main contexts: British society, the Jewish world, and the nonprofit sector. Adopting a sector-based approach, two data sources were collected and analysed: 45 interviews with employees, senior managers, and volunteers; and 102 online statements by 34 organisations within the sector. The empirical discussion traces the construction of three main social differences: Jewishness, race and ethnicity, and political-ideological difference. Conceptualising the Jewish nonprofit as an identity-based and a diaspora organisation, the findings shed light on the boundary work around the Jewish space and the Jewish community, the relations between Jewishness and whiteness at work, and the role of Israel-Palestine in shaping diversity debates in the diaspora. The study contributes to understanding the contextual and relational nature of diversity; disputes and paradoxes around identity in organisations; and diversity-inclusion gaps. It suggests the idea of the political case for diversity, elaborates debates around whiteness at work, and contributes to nonprofit literature around the construction and role of communities.