The article examines informal carers’ experiences of co-producing care, combining notions of carer roles with the strategies used by carers in their interactions and negotiations with the health and social services. The aim is to contribute to the theoretical understanding of carers’ role in co-production. On the basis of interviews with carers with a wide range of experiences, we find that they wish to be treated as co-producers, but their roles and impact depend on whether they are tasked with co-producing knowledge or co-producing care. In knowledge production, informal carers are encouraged to take active part and use their voice to further the interests and values of the person in need of support. However, their impact is conditional on their initiatives being recognised by formal caregivers and, to some extent, the person in need of support. In providing care, their efforts largely go unnoticed, and they are less likely to make their voices heard, but their room to manoeuvre appears to be greater. However, when the work of carers is not recognised, formal carers forego resources that are important to the quality and effectiveness of care. The findings, we argue, have important implications for the theory and practice of co-production.