More than 30,000 people have a traumatic brain injury (TBI) each year in New Zealand. Despite improvements in acute care, our research highlights people with TBI and their whānau live with ongoing and significant disabling consequences. Providing support by people who have successfully been through the same situation (peer mentoring) is a promising strategy for enhancing life after TBI. Our HRC funded feasibility study of a novel, NZ-appropriate peer mentoring programme for people with TBI promoted a sense of hope, gave participants confidence to re-engage in community activities, and supported the development of personalised strategies for living well. The proposed randomised pragmatic waitlist trial with process evaluation aims to test the effectiveness of peer mentoring for improving participation, health and well-being outcomes following TBI. We will work with key funders and providers to explore key process variables relating to context and implementation to underpin a framework for ongoing service provision.