Nearly half of people who experience a mild brain injury, also known as concussion, experience on-going symptoms and difficulties functioning in everyday life. Treatment is currently provided by ACC and includes provision of psychological support. However, there is currently a lack of scientific evidence as to the best approach to use. Acceptance and Commitment Therapy also known as ACT is believed to be one of the most promising approaches that also fits well with the Māori worldview. This feasibility study will test the whether the ACT approach can be tested within a community concussion service, whether the programme is culturally responsive, the ability to recruit patients into the study and to see whether there are any beneficial effects. Addressing these issues will allow us to conduct a full scale clinical trial to determine clinical effectiveness of this treatment for people who experienced a mild brain injury.