Tax measures must be adopted unanimously by the Member States. The European Parliament has the right to be consulted on tax matters, except on budgetary-related issues, for which it is co-legislator.

The power to tax is in the hands of the Member States, with the EU having only limited EU competences. As EU tax policy is geared towards the smooth running of the single market, the harmonisation of indirect taxation was addressed before direct taxation. The fight against harmful tax evasion and tax avoidance has become a recent policy priority.