This paper reports the findings of a scoping study designed to describe the evidence base with regard to support workers in social care in the United Kingdom and to identify gaps in knowledge. Multiple bibliographic databases were searched for studies published since 2003. The results revealed that the support worker role, though not well-defined, could be characterised as one aimed at fostering independence among service users, undertaking tasks across social and health-care, and not being trained in, or a member of, a specific profession. The studies identified were predominantly small-scale qualitative projects which considered issues such as role clarity, training and pay, worker satisfaction, service user views and the amount of time support workers are able to spend with service users compared to other staff. The review concluded that the research base lacks longitudinal studies, there is definitional confusion and imprecision, and there is limited evidence about employment terms and conditions for support workers or about their accountability and performance. The desirability and value of training and how it is resourced need further analysis. It is concluded that moves to self-directed support or personalisation and the increased reliance on and use of support workers, in the form of personal assistants, call for closer scrutiny of the role.