In this chapter, Luca Cerioni continues the discussion and examines priorities pursued by the EU in the area of corporate tax harmonisation since 2001. He shows that the EU’s priorities appear to have switched from the removal of crossborder tax obstacles to the fight against tax avoidance and harmful tax competition. Cerioni argues that the legislative measures that have been introduced for this purpose risk targeting structures in the absence of wholly artificial arrangements as intended under the case law of the Court of Justice. Furthermore, such legislative measures may be ineffective in tackling forms of aggressive tax planning allowed by the kind of tax competition that has been consistently regarded as ‘fair’. The author argues that, on the basis of legislative measures enacted, the EU may have overreacted against tax avoidance but underreacted against its ultimate cause, that is, against harmful tax competition. A significant challenge arises for future research in order to find the best way to achieve coordination of measures which counter tax avoidance and harmful tax competition.