Independent regulatory authorities (IRAs) today have considerable competences. They can regulate and supervise the behaviour of market and societal parties, and set prices for goods and services. They can enforce regulations through fines and ‘naming and shaming’. Thirdly, they have quasi-judicial functions. Yet IRAs are independent in their decisions from both the elected political sphere and sectoral interests. This makes the question whom, or what, these authorities represent a salient one. Yet this question is not often discussed in the literature. In the literature on IRAs, three approaches towards the independent bodies can be distinguished, that either stress their ‘inherent’ legitimacy based on the quality of their decisions, emphasize their ‘derived’ democratic legitimacy from elected institutions, or argue their legitimacy derives from their relations with a variety of actors. Commonly, however, IRAs are considered ‘unrepresentative’ because of their unelected status. In this thesis, it is argued that IRAs should nevertheless be considered non-electoral representative claimants. Viewing IRAs as such yields positive and normative benefits, that may be employed in the further study of these agencies, including in the three outlined approaches. To make this argument, four IRAs in the Netherlands – the telecommunications regulator OPTA, energy regulator NMa Energy Chamber, financial supervisor AFM, and healthcare regulator NZa – are studied from the perspective of the theorization of representative claims by Michael Saward (2010). Representation in this framework is considered a rhetorical and discursive process, consisting of claims to act or speak for others and the simultaneous construction of constituencies in these claims. Representative claims may have electoral and non-electoral resources: they can be made by politicians, interest groups, government organizations, ombudsmen and individuals alike. Likewise, representative claims can be received and accepted or rejected by the targeted constituency on ...