One of the two main Treaties that form the basis of EU law. The other is the Treaty on the Functioning of the European Union (TFEU).

The Treaty on European Union (TEU) sets out the European Union's purpose, democratic principles, institutions and governance framework, as well as provisions on enhanced co-operation, external action and the EU's common foreign and security policy.

As from 1 December 2009, the Lisbon Treaty significantly revised the both the TEU and the TFEU.

The TFEU and TEU are accompanied by many protocols and declarations, as well as the Charter of Fundamental Rights of the EU.

For further details, see: