Common factors, such as the working alliance, positive expectations, and psychoeducation have been robustly related to outcome in studies of psychotherapy. As a multicomponent treatment for borderline personality disorder (BPD), Mentalizationbased treatment (MBT) includes introductory group-based psychoeducation on core features of personality functioning, BPD, the treatment program and disorder-related personal management. Generally, few studies have investigated patients' views on how psychoeducation works. This study aimed to explore their experience of the group-based psychoeducation. Twelve patients who had attended the introductory group-based psychoeducation in MBT participated. Qualitative interviews were analyzed using Interpretative Phenomenological Analysis. MBT psychoeducation was found helpful in itself and in the further treatment process. Identified experiences related to the group (feeling less ashamed, learning from others, feeling different from others), acquisition of "tools" for better personal management (the psychoeducational content; putting new knowledge into practice), preparation for longer term therapy (therapy became more trustworthy, easier to understand, felt more effective), and demanding aspects (problems with attendance or concentration). This qualitative study is the first to present patients' own experiences of psychoeducation as part of MBT and suggests that psychoeducation is a powerful and facilitating intervention. Careful patient selection may further optimize its potential.