This article examines how the core European Union Treaties and the Court of Justice of the European Union have sought to give effect to the principle of democracy within the European Union legal order. It explains that the complexity of the legislative procedure, with its checks and balances between the relevant European Union institutions, is a reflection of the need to ensure effective participation by all of them. The three main institutions of the European Union, namely the Parliament, the Council, and the Commission, represent different legitimate interests which do not always coincide. The fact that European Union legislation is multilingual and often expressed in broad terms presents its own particular challenges to the Court of Justice of the European Union when it is asked to interpret that legislation. For its part, the Court of Justice of the European Union is sensitive to the wishes of the legislature, and therefore has been willing to modify previous case law based solely on the Treaties where the legislature has subsequently signalled its intention to apply the relevant Treaty provisions in a different manner.