This thesis aims to give an overview of the different meanings that the European courts have been given in their decisions to the principle of legal certainty and of how the respect of this principle can enhance the economic growth of Member States Indeed, the principle of legal certainty ensures the necessary predictability about competition and internal market rules that is fundamental in order to appeal foreign investors to Europe. This goal could be better achieved if this principle can be applied also beyond the competences of European Union listed in the Treaties, like it is well explained in the final part of this work.
