Background: Group schema therapy is an emerging treatment for personality and other psychiatric disorders. It may be particularly suited to individuals with complex trauma given that early abuse is likely to create maladaptive schemas. Aims: This pilot study explored the feasibility and effectiveness of a 4-week in-patient group schema therapy programme for adults with complex trauma in a psychiatric hospital setting. Method: Thirty-six participants with complex trauma syndrome participated in this open trial. Treatment consisted of 60 hours of group schema therapy and 4 hours of individual schema therapy administered over 4 weeks. Feasibility measures included drop-out rates, qualitative interviews with participants to determine programme acceptability and measures of psychiatric symptoms, self-esteem, quality of life and schema modes pre-, post- and 3 months following the intervention. Results: Drop-out rate for the 4-week program was 11%. Thematic analysis of interview transcripts revealed four major themes: connection, mode language explained emotional states, identifying the origin of the problem and the emotional activation of the programme. Measures of psychiatric symptoms, self-esteem and quality of life showed improvement post-treatment and at 3 months post-treatment. There was a reduction in most maladaptive schema modes pre-/post-treatment. Conclusions: A group schema therapy approach for complex trauma is feasible and demonstrates positive effects on psychiatric symptoms and maladaptive schemas.