Treaty on the Functioning of the European Union

The Treaty on the Functioning of the European Union (TFEU) is one of two treaties forming the constitutional basis of the European Union (EU), the other being the Treaty on European Union (TEU. It was previously known as Treaty Establishing the European Community (TEC).

The Treaty originated as the Treaty of Rome (fully the Treaty establishing the European Economic Community), which brought about the creation of the European Economic Community (EEC), the best-known of the European Communities (EC). It was signed on 25 March 1957 by Belgium, France, Italy, Luxembourg, the Netherlands and West Germany and came into force on 1 January 1958. It remains one of the two most important treaties in the modern-day European Union (EU).

Its name has been amended twice since 1957. The Maastricht Treaty of 1992 removed the word "economic" from the Treaty of Rome's official title and, in 2009, the Treaty of Lisbon renamed it the "Treaty on the Functioning of the European Union".