Europol (portmanteau of European Police Office) is the European Union's criminal intelligence agency. It became fully operational on 1 July 1999.

The establishment of Europol was agreed to in the 1992 Maastricht Treaty, officially known as the Treaty on European Union (TEU) that came into effect in November 1993. The agency started limited operations on 3 January 1994, as the Europol Drugs Unit (EDU). In 1998 the Europol Convention was ratified by all the member states and came into force in October. Europol commenced its full activities on 1 July 1999.

Europol allocates its resources (625 staff, of these, approximately 120 Europol liaison officers (ELOs)) from its headquarters in The Hague. The size of Europol belies the fact that they are in constant liaison with hundreds of different law enforcement organisations, each with their own individual or group seconded to assist Europol's activities.

As of 2007, Europol covers all 27 member states of the European Union. In order to fight international organised crime effectively, Europol cooperates with a number of third countries and organisations as follows (in alphabetical order): Albania, Australia, Bosnia and Herzegovina, Canada, CEPOL (European Police College), Colombia, Croatia, Eurojust, European Central Bank, European Commission, European Monitoring Centre for Drugs and Drug Addiction, Republic of Macedonia, Frontex, Iceland, Interpol, Moldova, Norway, OLAF (European Anti-Fraud Office), Russian Federation, Switzerland, SitCen (EU Joint Situation Centre), Turkey, United Nations Office on Drugs and Crime, USA, World Customs Organisation. This is done on the basis of cooperation agreements concluded in accordance with the Europol Convention. The Europol External Strategy defines the framework within which Europol is to develop its activities with regard to third partners.

It has been decided that Europol will be converted to a full EU agency on 1 January 2010, thus simplifying the procedure to reform it; until then, reforms have to be made through an amendment to the Europol Convention.