Abstract
Diversity, equity and inclusion (DEI) initiatives are now embedded in organisational strategy, yet a growing stream of research and practice reveals that well-intended efforts can produce unintended negative outcomes. This developmental paper advances early-stage theorising on the ill effects of DEI and outlines a programme of empirical research to examine how they arise and how leaders can mitigate them. Synthesising critical streams in organisational behaviour and social psychology, we identify recurring harms: perceived reverse discrimination and identity-based tensions; compliance-driven bureaucracy and performative signalling; identity essentialism; a psychological safety paradox and self-censorship; diversity fatigue and the diversity tax burdens on marginalised employees; and distrust when espoused values misaligned with everyday practises. We integrate these insights into a provisional framework identifying for mechanisms that amplify ill effects: (1) misalignment between stated values and practise; (2) top-down imposition without dialogue; (3) inadequate managerial competence for identity laden conversation; and (4) tokenistic implementation under resource constraints. The study outlines a qualitative multi-case design to examine these mechanisms across contexts and to develop design principles that avoid backfire, false progress and negative spillovers. By making the potential harms to DEI discussable, this study aims to enable more credible, dialogic and sustainable inclusion practises.