Tackling tax avoidance is high on the agenda of states. The latest US approach to this problem was to enact the Foreign Account Tax Compliance Act (FATCA), which, in certain respects, overrides its existing tax treaties with its FATCA partners. In this article, the author provides an overview of the main FATCA provisions and implementation process, which serves as the basis for a discussion on the extraterritorial scope of FATCA and its legal implications.