Cross-border economic entities often face double taxation in many cases. To avoid this competitive distortion, bilateral agreements in the form of double taxation treaties (DTA) exist. In Germany, the instrument of so-called Treaty Overriding has been in place for more than 20 years, which describes the legal situation of unilateral deviation from a DTA. Ronald Gebhardt sheds light on this highly complex phenomenon from the perspectives of international, constitutional, and EU law, also examining the economic implications for the first time and providing a comprehensive overall systematization.