Individual cognitive behaviour therapy for psychosis (CBTp) is a recommended treatment in the acute phase and beyond. However, less is known about the effectiveness of group CBTp in acute care. This mixed methods study explored the implementation and effectiveness of brief group CBTp with inpatients. This prospective trial compared inpatients who received either a four week group CBTp program or treatment as usual (TAU). Participants (n = 113 at baseline) completed self-report measures of distress, confidence and symptoms of psychosis at baseline, post-intervention and one month follow up. CBTp group participants also completed a brief open-ended satisfaction questionnaire. Using complete case analysis participants who received CBTp showed significantly reduced distress at follow up compared to TAU and significantly increased confidence across the study and follow up period. However, these effects were not demonstrated using a more conservative intention-to-treat analysis. Qualitative analysis of the satisfaction data revealed positive feedback with a number of specific themes. The study suggests that brief group CBTp with inpatients may improve confidence and reduce distress in the longer term. Participants report that the groups are acceptable and helpful. However, given the methodological limitations involved in this ‘real world’ study more robust evidence is needed.