Following the September 11, 2001, terrorist attacks, using a set of policy programs, strategy documents, and a list of priorities as foundations, the EU has aimed to coordinate its Member States’ policies, harmonize national legislation, and even support some operational work conducted by national authorities. Almost 25 years later, however, the EU enforcement capabilities remain relatively weak, and there is a lack of effective coordination between EU institutions/agencies and EU Member States in several important areas (e.g., prevention). Thus, the primary goal of the proposed project is to provide a comprehensive theoretically informed analysis of the evolution of the EU counterterrorism policy, with an emphasis on the recent developments (e.g., Brexit), that identifies and explains both the current shortcomings and the tangible “value-added” that the EU provides to the national counterterrorism policies of its Member States.