The article addresses the implications of Prevent and Channel for epistemic justice. The first section outlines the background of Prevent. It draws upon Moira Gatens and Genevieve Lloyd’s concept of the collective imaginary, alongside Lorraine Code’s concept of epistemologies of mastery, in order to outline some of the images and imaginaries that inform and orient contemporary counter-terrorist preventative initiatives, in particular those affecting education. Of interest here is the way in which vulnerability (to radicalisation) is conceptualised in Prevent and Channel, in particular the way in which those deemed ‘at risk of radicalisation’ are constituted as vulnerable and requiring intervention. The imaginary underpinning such preventative initiatives is, I argue, a therapeutic/epidemiological one. If attention is paid to the language associated with these interventions, one finds reference to terms such as contagion, immunity, resilience, grooming, virus, susceptibility, therapy, autonomy, vulnerability and risk—a constellation of images/concepts resonant with therapeutic and epidemiological theories and practices. I outline some of the implications of this therapeutic/epidemiological imaginary for epistemic injustice. If people, in this case, students, teachers and parents, feel that their voice will not be given credence, this leads to testimonial injustice. If one group is constituted as a suspect community, this risks hermeneutical injustice for that group—a situation facing Muslims at present. Given the requirements for educators and educational institutions to enact this particular iteration of preventative counter-terrorist legislation, the way in which vulnerability (to radicalisation) is understood and operationalised has direct bearing upon education and the educational experience of all stakeholders, in particular in relation to the conditions for epistemic justice.