Background and aims: This study explored therapists’ and clients’ experiences of paranoia about the therapist in cognitive behaviour therapy. Method: Ten therapists and eight clients engaged in cognitive behaviour therapy for psychosis were interviewed using a semi-structured interview. Data were analyzed using thematic analysis. Results: Clients reported experiencing paranoia about their therapist, both within and between therapy sessions. Therapists’ accounts highlighted a number of dilemmas that can arise in responding to clients’ paranoia about them. Conclusions: The findings highlight helpful ways of working with clients when they become paranoid about their therapist, and emphasize the importance of developing a therapeutic relationship that is radically collaborative, supporting a person-based approach to distressing psychotic experience.