This report written by Dr Dia Anagnostou and Dr Dimitris Skleparis was completed in the frame of the RAD MONITOR project. Its main objective is to provide a background study on radicalisation in Greece and the various forms that it takes: the extreme left radicalization and its transmutation into the anti-authoritarian movement, the far-right radicalization, the Islamist radicalization, and football ‘hooliganism”. It provides an overview of past and current radicalisation trends, the social groups most vulnerable to each form of extremism, their repertoires of action, and the institutional responses of Greek authorities