This collection of Brain Impairment papers highlight the latest advances in collaboration, co-production, and co-design with people who have a brain impairment. It captures the 'state of the art' in research practices that prioritise authentic involvement, from the earliest stages of idea development through to study design and implementation. The collection showcases both the successes and challenges of inclusive approaches, emphasising their critical role in producing meaningful and impactful research outcomes. Contributions span a range of brain impairment aetiologies, including brain injury, stroke, and dementia, reflecting both the capacity and generosity of people with living experience in generating increased diversity and richness in research exploring rehabilitation practices.