The legal concepts of ‘statehood’, ‘de facto authorities’ and ‘occupation’ are used for analysing both the type of control that unrecognized political entities in Europe exercise over their territory and population, and their relationship with the international order. The use of such terms in political discourse and policy documents will legitimize or delegitimize the claims of the parties to a conflict. They will have a direct political impact on how the EU mediates these conflicts and engages with the authorities and the population of unrecognized entities. Once they become part of a political practice, legal concepts may allow or even enlarge the scope of potential engagement, but they may also impose severe constraints on EU engagement, and even rule it out almost completely. Their application leads to disagreements within the EU. The concept of ‘occupation’ is particularly contentious: EU member states differ in their use of it with regard to particular conflicts, and in this respect divergences also appear within the institutional framework of the European Union—between the European Commission, the Council, the Parliament and other institutions. An analysis of the use of legal concepts in political discourse and policy documents goes beyond international law: an analysis within the field of political science is required.