This study evaluated the effectiveness of a school-based group intervention designed for children who have experienced trauma. Twenty-six children (aged 11-15 years) who were refugees or asylum-seekers from war-affected countries participated. The manual-based intervention consisted of cognitive-behavioural therapy (CBT) techniques and was implemented within secondary schools. The treatment group ( n = 15) received six sessions of group CBT over a 6-week period, while the control group ( n = 11) were placed on a waiting list for 6 weeks and then invited to enter treatment. Children in the CBT group showed statistically significant, but clinically modest improvements following the intervention, with decreases in overall severity of post-traumatic stress symptoms. Significant improvements were also found in overall behavioural difficulties and emotional symptoms. Children in the waiting list control group did not show any improvements over the same period. However, follow-up data, which were only available for a small subset of eight children, suggest that gains in the CBT group were not maintained at 2-month follow-up.