This chapter addresses the metaphysics of biological kinds. We can discern a spectrum of views from anti-realism with regard to species and kinds that typically takes the form of pluralism or nominalism, and is sometimes motivated by the empiricist stance, through to species or higher-taxa realism—requiring at least the SSR stance, the epistemic stance that licenses ontological commitment to the explicit subject matter of science—through to views that require the MoS stance, the stance that licenses belief in the existence of the implicit subject matter of biology, such as natural kinds, essences and dispositions. The epistemic stance framing helps to uncover the metaphysical and epistemological commitments of the various positions taken in the recent debates concerning natural kinds. The epistemic account of natural kinds is, I argue, often motivated by the kind of rejection of metaphysical explanation characteristic of the empiricist stance, while the mind-dependent view that is sometimes called weak realism involves, I argue, a somewhat unstable combination of the empiricist and realist stances. The stronger ‘metaphysical’ account of kinds, purports to be an expression of the MoS stance, although it is one which, in its a priori speculations about the metaphysical status of kinds—whether they are universals, or are sui generis, etc.—arguably risks veering off the cliff of naturalised metaphysics into armchair metaphysics territory.