Transnationality is a principle of carrying out an action across national borders, so as to have effects at a more general level. It is commonly referred to with reference to the actions of the European Union, in distinction to 'international' (among national governments and controlled by them) or 'supranational' (suggesting powers delegated to a higher level of government).
According to the principle of subsidiarity, actions ought to be taken at the lowest level of government possible, so as to maximise democratic accountability and responsiveness to people's needs. The actions of the EU are therefore often justified by reference to 'transnational added value'. This means that the lessons of the experience of one country may prove useful in another.
Transnationality is a strong dimension of the EU Cohesion Policy and specifically of the way that ESF and ERDF actions can be improved. It also features within the methodologies for the open method of coordination. Transnationality was one of the four guiding principles of EQUAL.