Globalization redefines the relationship between law and space, resulting in the emergence of transnational administrative law in a globalizing legal space. I aim to shed light on transnational administrative law by examining how administrative law relates to the process of European integration. I argue that the idea of administrative legitimation is at the core of this relationship. In the European Union, transnational administration grounds its legitimacy on the fulfilment of administrative law requirements. However, given that in the European Union, administrative legitimation is rooted in Europe's constitutional transformation, I caution against the projection of Europe's experience onto global governance.