In this contribution, the author, who was a pupil of the late Prof. em. Frans Vanistendael and later became his successor at the Institute of Tax Law at KU Leuven, discusses the view of Prof. em. Vanistendael on tax abuse. Prof. em. Vanistendael took the position that there are multiple notions of tax abuse in EU law, depending upon whether abuse of primary or secondary law is at stake. The present author, however, argues that there is only a single notion of tax abuse which is incarnated in the general EU law anti-abuse principle that applies in all areas of tax law, but not necessarily with the same effect.