AbstractThis paper discusses how epistemic and ontological commitments shape different understandings of European Union (EU) law and why it matters. Many key debates on EU law—and some of the fiercest disagreements in European legal scholarship—go back to divergent epistemic and ontological commitments. While these philosophical commitments usually operate in the background, this paper foregrounds them. A core aim of the paper is to denaturalise the epistemic and ontological groundings of mainstream approaches to EU law and, thus, to demarginalise approaches more peripheral to the centres of power in EU law-making and in EU legal academia.