Questions of identity have returned to the centre of political debates in Europe. A key issue is that while the EU has greatly expanded its powers in key policy domains that traditionally have been the preserve of nation states, its political identity remains weak. The special issue examines the construction of the EU’s political identity (or identities), variations in its strength and the nature of its content. Drawing on studies both on European nation-state formation and on the EU’s identity, we take a topdown approach and analyse how EU institutions in different major policy domains have themselves sought to create political identity through policy making. We define the construction of EU political identity and set out empirically applicable indicators to assess political identity in policy making. We analyse the construction of identity through a process-oriented approach that explicitly includes contestation and the existence of rival political identities. Comparing across policy domains, we suggest that the ability of EU institutions to construct an EU political identity has been limited not only by existing national identities but also by the coexistence of rival EU political identities within policy domains. Hence, it has been difficult for EU institutions to establish a strong identity, with identity being strongest where there are clear external alternatives and limited rival identities within the EU.