Abstract One of the main issues in the debate on urban constitutionalism is how constitutions can recognize the increasingly important role of cities in relation to the nation-state. This paper examines what we talk about when we talk about city autonomy. This is a pressing question, particularly in the context of European unitary states. This paper pays special attention to the context of two of such states, namely the Netherlands and the United Kingdom (especially England). First, it explores the notion of subsidiarity, which implies that consideration should be given to the distinctiveness of the city as regards the allocation of power to the central and regional levels respectively. However, this idea in itself cannot justify the case for city autonomy, as the claim that the attribution of autonomous powers to cities may improve the quality of decision-making in the state as a whole needs additional empirical evidence. Second, it investigates the concept of city autonomy by exploring the fuzziness of the notion of the city. In addition, it introduces the concept of ‘spatial identities’ in order to explain the interdependence of (large) cities and their surrounding (rural) areas. Lastly, it concludes that if the importance of cities as constitutional actors is to be increased, it should be done so in an informal way rather than by the introduction of formal constitutional arrangements both from a pragmatic and a normative perspective.