ABSTRACT Increasingly intense, multifaceted, and integrated forms of surveillance are a central feature of Western national security attempts to counter the violence of “Islamic terrorism.” However, there has been a lack of research examining contemporary regimes of surveillance as profoundly racialized. This study examines how counterterrorism efforts are underpinned by ill-conceived accounts of radicalization that preemptively construct Muslim migrants as a threat to national security, thereby justifying practices of mass surveillance that further propagate racist discourses of uncertainty and risk. We advance an analysis of a racialized surveillant assemblage, which is generative of mutable, algorithmically determined profiles of the Muslim-as-terrorist. Such a regime of mass surveillance effectively puts all Muslims under suspicion. We highlight that, paradoxically, mass data-mining operations stifle, rather than aid, the identification of actual terrorist threats. This conditions a paranoid surveillant racism, through which Muslim populations become modulated as an unknowable threat of death and destruction.