In cooperation with the courts of the Member States, the Court of Justice of the European Union (CJEU) ensures the uniform interpretation and enforcement of European Union Law. The CJEU is based in Luxembourg and includes two courts: the General Court (established in 1988), and the Court of Justice. José Luís da Cruz Vilaça served as Advocate General and Judge at the Court of Justice; and he also served as the first President of the General Court, at the time named Court of First Instance.

Various types of proceedings may be brought before the CJEU.

• Action for Annulment:  Seeks the annulment of the acts of institutions, bodies, offices or agencies of the European Union, in particular of the decisions of the European Commission related to competition and public aid.
• Action for Failure to Act: An action brought against an institution, body, office or agency of the European Union for breach of a duty to act.
• Infringement Proceedings: An action brought against a Member State or a national Central Bank for breach of its obligations under the Treaties or the Statute of the European Investment Bank, the European System of Central Banks, or the European Central Bank.
• Reference for a Preliminary Ruling: Whenever a question relating to the interpretation or validity of European Union Law is brought before a national court, the latter may request the Court of Justice to offer a preliminary ruling on it. In certain circumstances, national courts are required to do so.
• Non-Contractual Liability: The European Union shall compensate for damage caused by its institutions or their agents in the performance of their duties. In addition, Member States must compensate for damages resulting from breaches of EU Law and their liability may be brought before national courts.
• Precautionary Measures: The CJEU may order precautionary measures in the cases brought before it.