The aim of this study was to evaluate a brief psychologically informed coping skills group intervention for adults with severe prolonged symptoms following mild traumatic brain injury (mTBI).Patients attended an education session about mTBI; 22 patients completed an additional coping skills group intervention, 16 declined/stopped the intervention early and 19 were not offered the intervention. At follow-up, patients who completed the intervention reported a similar degree of symptom improvement and disability as those who did not complete the intervention. The majority of patients who completed the intervention were satisfied with it and perceived it to be credible.The coping skills intervention was not associated with measurable clinical benefit. Recommendations for improving psychological interventions for mTBI are discussed.