The European Parliament (Europarl or EP) is the only directly elected parliamentary institution of the European Union (EU). Together with the Council of the European Union (the Council), it forms the bicameral legislative branch of the Union's institutions and has been described as one of the most powerful legislatures in the world. The Parliament and Council form the highest legislative body within the Union. However their powers as such are limited to the competencies conferred upon the European Community by member states. Hence the institution has little control over policy areas held by the states and within the other two of the three pillars of the European Union. The Parliament is composed of 785 MEPs (Member of the European Parliament), who serve the second largest democratic electorate in the world (after India) and the largest trans-national democratic electorate in the world (342 million eligible voters in 2004).

It has been directly elected every five years by universal suffrage since 1979. Although the European Parliament has legislative power that such bodies as those above do not possess, it does not have legislative initiative like most national parliaments. While it is the "first institution" of the European Union (mentioned first in the treaties, having ceremonial precedence over all authority at European level ), the Council has greater powers over legislation than the Parliament where codecision procedure (equal rights of amendment and rejection) does not apply. It has, however, had control over the EU budget since the 1970s and has a veto over the appointment of the European Commission.

The European Parliament has two meeting places, namely the Immeuble Louise Weiss in Strasbourg, France, which serves for plenary sessions and is the official seat and the Espace Léopold complex in Brussels, Belgium, the smaller of the two, which serves for preparatory meetings and complementary, non-plenary sessions. The cost of having all MEPs and their staff moving several times a year from one place to another has been of concern to some. The Secretariat of the European Parliament, the Parliament's administrative body, is based in Luxembourg.

The President of the European Parliament (its speaker) is currently Hans-Gert Pöttering (EPP), elected in January 2007. He presides over a multi-party chamber, the two largest groups being the European People's Party-European Democrats (EPP-ED) and the Party of European Socialists (PES). The last Union-wide elections were the 2004 Parliamentary Elections, however Romania and Bulgaria joined in 2007 and are electing their members this year (see European Parliament election, 2007); the next union-wide parliamentary elections are in 2009 (see European Parliament election, 2009).