The chapter moves through a brief history of ontology and trends in contemporary analytic ontology before investigating common positions in musical ontology such as Platonism (Kivy, Dodd), compliance theory (Goodman, Elgin), continuant theory (Rohrbaugh, Magnus), and performance theory (Davies, Currie). After evaluating the strengths and weaknesses of each of these, it argues for a version of continuant theory as an account of musical ontology that makes sense of musical practices and intuitions while honouring naturalistic philosophical commitments. Moreover, I suggest that the inherently “shaky” nature of undecidable claims within ontology (musical or otherwise) means that ontological approaches should not take fact-stating as their sole objective. Rather, ontological statements may function both descriptively and prescriptively: as such, ontology possesses a key regulative purpose within our theoretical discourse.