Diversity is essential not only to the flourishing of human life, but to all life on our planet. However, many Diversity, Equity, and Inclusion (DEI) efforts fall prey to diversity-washing or “lip service” approaches. The concept of ontological diversity—or the diversity of worldviews—offers a lens through which to critically assess whether a given DEI initiative is having the impact it aims to have. By examining underpinning worldviews, this lens enables consideration of the ways that everyday practices, policies, or ways of being within systems or organizations reproduce systemic inequities in ways that continue to exclude certain worldviews, such as Indigenous worldviews. This ultimately works against the potential for DEI efforts to have the structural or lasting effects they require in order to go beyond diversity-washing. Promoting the necessity for a pluriverse of worldviews and lifeways, the call to consider ontological diversity in DEI efforts thus draws attention to dominant, taken-for-granted ways of thinking and being at both the individual and institutional level. Drawing on Indigenous theory, decolonizing scholarship, critical race theory, deep ecology, phenomenology, and lessons from two contemporary justice movements, the author shows that one way DEI efforts can safeguard against the risk of diversity-washing is by ensuring that they themselves include and attend to the need for diverse ontologies and worldviews within their focus and goals.