This article explores foster children’s agency in their encounters with Child Protection Services (CPS). The article draws on semi-structured interviews with former and present foster children aged 18–22, who have grown up in kinship foster homes in state custody. During their childhood, there has been increased emphasis on client participation within CPS. Based on a sociological framework we understand the relationship between CPS and its clients as an asymmetric power relation. The analyses demonstrate that foster children in kinship care are actors with different motivations and competencies for participation and co-determination within CPS. We point out four types of agency, which range from the agent as an equal, active participant in a cooperative relationship with CPS – to the agent as a powerless client in a relationship marked by distrust.