In 2021, the European Commission published the proposal for an EU Artificial Intelligence Act (AIA), which specifically aims to prohibit “an AI system that deploys subliminal techniques beyond a person’s consciousness in order to materially distort a person’s behaviour.” The paper argues that this prohibition is one of the key clauses in the AIA, given the growing technological means by AI and related technologies, such as brain–computer interfaces (BCIs), functional magnetic resonance imaging (fMRI), robotics and big data etc, to interfere with a person’s thoughts and behavior as well as to cause wider societal harms ranging from inciting hatred and violence to the interference with the outcomes of elections. Given the so-called “Brussels effect” and the growing global interconnectedness of technologies, this paper argues for the need to address the issue of subliminal AI systems globally as it resonates in the 2021 UNESCO Recommendation on the Ethics of Artificial Intelligence.