The European Synchrotron and FEL user organisation (ESUO) represents about 30.000 users of the European synchrotrons and FEL light sources.

At present 30 European countries (including Turkey and Israel) are ESUO members and are represented by delegates. The general missions of ESUO are to coordinate the synchrotron and FEL radiation user activities in Europe and to provide support to the users in order to get access to synchrotron and FEL beamlines in Europe.