In this article, the author discusses implementation of the EU Anti-Tax Avoidance Directive (2016/1164), as amended (ATAD) in Portugal. The article covers all of the ATAD’s rules, i.e. interest limitation, exit taxation, general anti-abuse, controlled foreign companies and hybrid mismatch rules. The author presents some features of the rules existing at the time of implementation and comments on the main changes that took place as a result of implementation of the ATAD.