The digital age, while promising tools to advance health care, has simultaneously ushered in new forms of power asymmetry, with extractive data practices risking the perpetuation of historical injustices and structural inequities. Achieving epistemic justice in health data governance initiatives demands a fundamental shift in how knowledge is produced, legitimised and applied. It requires a concerted effort to delink from colonial epistemic hierarchies and to embrace the rich plurality of ways of knowing, ensuring that health data genuinely serves the well-being and prioritises the self-determination of those from all walks of life. This article critically examines Transform Health’s equity- and human rights-based ‘Health Data Governance Principles’ through a decolonial lens, interrogating their potential to foster equity in the rapidly expanding field of digital health. Grounded in a decolonial imperative, the article challenges dominant epistemologies that underpin current global health frameworks. The conceptual foundations and practical applications of the Health Data Governance Principles are then explored in light of the findings of an empirical study undertaken by the author which examined the Principles themselves, organisational perceptions thereof, and efforts towards their operationalisation. In particular, it interrogates whether these principles align with and address the needs and values of historically marginalised communities. Central to this analysis is the introduction of a decolonial nexus that brings into relation the decolonial concepts of ‘health data justice’, ‘epistemological delinking’ and the ‘vernacularisation of human rights’. This approach is intended to not only to expose epistemic injustice within prevailing health data governance models but also to centre emancipatory praxis in reclaiming knowledge, rights and representation in digital health agendas.