To lose freedom of thought (FoT) is to lose our dignity, our democracy and our very selves. Accordingly, the right to FoT receives absolute protection under international human rights law. However, this foundational right has been neither significantly developed nor often utilized. The contours of this right urgently need to be defined due to twenty-first century threats to FoT posed by new technologies. As such, this paper draws on law and psychology to consider what the right to FoT should be in the twenty-first century.