Background: This study investigated which factors are associated with the therapeutic relationship in Cognitive-Behavioural Therapy for psychosis (CBTp). Method: Measures were taken between sessions two to nine in 24 therapist-client dyads. Clients and therapists completed the Working Alliance Inventory and measures of client (gender, age, ethnicity, positive and negative symptoms of psychosis, length of illness, admissions, social contacts, employment, cognitive insight, reaction to hypothetical contradiction), therapist (empathy, expertness, attractiveness, trustworthiness, number of years qualified and previous CBTp clients seen, confidence in CBTp), and therapy (number of sessions and CBTp interventions carried out, presentation of a formulation) factors. Results: On average, clients and therapists rated the therapeutic relationship as good, with clients giving higher ratings. None of the client variables was related significantly to the quality of the relationship. However, a number of therapist and therapy factors were linked to a better therapeutic relationship, namely clients' ratings of therapist empathy, expertness, attractiveness, and trustworthiness and, at trend level, a greater number of sessions and of CBTp interventions, and the presentation of a formulation. Conclusions: These results suggest that therapists are able to develop a good therapeutic relationship with clients with psychosis, regardless of the severity of the psychosis and the confidence and experience of the therapist, although non-significant findings need interpreting with caution due to the lack of a full range of therapeutic alliances. The findings also suggest that the basic tenets of CBTp, such as empathy and collaborative goals, may be important factors for the development of the therapeutic relationship.