This article critically analyses the novelty of the legal personhood of nature and, in particular, whether it signals cracks in the anthropocentrism of Western law. Drawing upon the work of Michel Foucault and Roberto Esposito, it contributes to the theorisation of environmental personhood by focusing on the biopolitical nature of personhood itself. It does so by engaging in a critical examination of the attribution of legal personality to the Whanganui River in Aotearoa New Zealand as the most detailed and sophisticated legislative example to date of legally personifying a natural thing. Working through three key conceptual terms in Foucault’s and Esposito’s work (population, personhood and immunisation), we demonstrate the way in which a biopolitical analysis raises questions about whether ascribing legal personhood to nature addresses anthropocentrism and its effects. We draw attention to the risk of ascribing legal personhood to nature, which is that, instead of signalling an ontological shift in the Western anthropocentric understandings of environment, it operates within and reinforces the dominant legal worldview–unless, that is, the granting of personhood to nature calls into question the dominant paradigm of personhood itself. The article concludes by suggesting alternative ways of developing human understandings of, and relationship with, nature.