'You have to let them do it themselves': Analyzing professional support in a befriending project

center dot Summary : In Western welfare states, public and non-profit service organizations are increasingly looking for ways to combine the efforts and expertise of professionals and volunteers to provide support and services to vulnerable target groups. However, little is known about how professionals and volunteers collaborate to provide these social services and support. The aim of this qualitative study is to analyze how professionals support volunteers in a befriending project, where volunteers provide support to people after they are released from prison. Therefore, we interviewed social workers (n = 4) and volunteers (n = 13). center dot Findings: Our results show that professionals provide tailor-made support to volunteers through different interventions: they share their knowledge and expertise, provide emotional support, and advise and coach the volunteers. Furthermore, in complex cases, professionals intervene to access appropriate social support and realize the rights of those involved. center dot Applications: Our findings provide a comprehensive perspective on how complementarity is constructed in the daily practice of collaboration between volunteers and professionals. Although professional interventions and support are necessary to address the needs of vulnerable people, volunteers offer a wider range of support than professionals alone can provide. Consequently, close collaboration between volunteers and professionals can result in a valuable response to the needs of people who have recently left prison. However, when a client's situation becomes complex and volunteers lack the skills, experience, and status to deal with it, professionals are advised to take over.