Diversity, equity and inclusion in One Health could crucially support functional health security by fostering prevention, but a change in mindset is needed.

In recent years, One Health (OH) has taken the lead as a systems-oriented method to foster transdisciplinary, multisectoral, and multi-actor action to promote global health security. However, operationalizing the OH approach is difficult since it requires equitable collaboration, communication and information sharing. The One Health High-Level Expert Panel's (OHHLEP) definition of OH lists key underlying principles at its core, which align with principles of diversity, equity and inclusion (DEI), and establishes that the application of the definition is incomplete without the adoption of these key principles. In this paper, we argue that, by overcoming the barriers that hamper OH adherence to DEI principles, the operationalization of the OH approach could be significantly enhanced to support global health security. We built on the key underlying principles included in the OHHLEP 2022 definition of OH to map barriers preventing its full-scale implementation and to identify inclusive avenues to promote the compliance of OH with its core principles. A scoping review of the literature and consultations with 10 OH professionals from different disciplinary backgrounds, regions of the world and levels of experience were performed. The barriers to the full adherence of OH to its underlying principles that emerged from this study were grouped into five categories: mindset, behaviors and awareness, conceptual, structural, power dynamics, and governance and implementation. Crucially, the engagement of diverse sectors and disciplines notably the environmental and social sciences; of different actors from communities and young people to donors and OH professionals, including the private sector; and of underrepresented groups, such as Indigenous peoples, farmers, fishers, representatives from low- and middle-income countries, and especially women across these groups, all intimately connected to the drivers of emerging health threats, is not only critical for realizing DEI principles in OH, but also to promote more effective prevention strategies and thus enhance global health security.