The term "treaty override" has acquired a specific connotation for tax treaty purposes, which requires an in-depth analysis. There is a tendency for domestic legislation to be passed or proposed (or court cases decided) which may override provisions of tax treaties. Despite the many conflicts and uncertainties about what tax treaty override exactly is and the exact point in time when tax treaty override occurs, its implications have not until now been analysed in a systematic manner. This book develops an interpretative process aimed at clearly detecting cases of tax treaty override, and presents a model that is applicable every time such a case needs to be identified. In the course of the analysis the author tests the model under numerous specific national regimes. Among the many elements of tax treaty override dealt with are the following:rn- effects of international tax law within national legal orders;rn- impact of the functioning and structure of the OECD Model Convention on tax treaty override;rn- tax treaty override as a violation of international law and the Draft Articles on State Responsibility;rn- implications of the OECD's 2013 Base Erosion and Profit Shifting (BEPS) action plan;rn- relation between tax treaty provisions and national anti-abuse provisions;rn- consequences deriving from the application of the "saving clause" of the US exit tax regime;rn- the "re-entry charge" in the United Kingdom;rn- fictitious income/capital and fictitious residence;rn- the transactional approach in CFC regimes; andrn- the need to guarantee protection to third states that conclude tax treaties with EU Member States.