In this study, we aimed to identify processes that enabled the involvement of a person with complex speech and motor disorders and the parent of a young person with these disorders as co-researchers in a U.K. research project. Semi-structured individual and focus group interviews explored participants’ experiences and perceptions of public involvement (PI). Sixteen participants were recruited, with representation from (a) the interdisciplinary project team; (b) academics engaged in discrete project activities; (c) individuals providing organizational and operational project support; and (d) the project’s two advisory groups. Data were analyzed using Framework Analysis. Five themes were generated: (a) the challenge of defining the co-researcher role; (b) power relations in PI; (c) resources used to enable PI; (d) perceived benefits of PI; and (e) facilitators of successful PI. Our findings provide new evidence about how inclusive research teams can support people with complex speech and motor disorders to contribute meaningfully to co-produced research.