Over the last years, the European Union passed various provisions to strengthen the independence of European audit oversight systems. However, a systematic and encompassing comparison of the reform outcomes across the European Member States is still missing. This paper therefore explores the various forms of regulation that are in place among the EU Member States and the diverse ways of responding to common European legislative initiatives and international harmonization pressure. Although observers predicted that market pressures would reduce the differences in the regulation of statutory auditors over time, the analysis reveals significant differences in the way in which Member States organize their public oversight systems