According to the UN Convention on the Rights of the Child and Swedish legislation, children have the right to participate in child protection proceedings. The aim of this paper is to describe and analyse the notion of age and maturity in child protection proceedings in order to elucidate how these aspects could influence children's rights to participate. We focus on the view of three groups of actors involved in child protection proceedings in Sweden—social workers, lawyers, and laypersons in social welfare boards and administrative courts—and on how children's age and maturity should be taken into consideration in decisions on their participation in court. The analysis is based on survey data. The study found that social workers, laypersons, and lawyers have different views on when children are old enough to have the right to litigate in court. Additionally, there is no consensus on how the maturity of the child can be assessed to inform the decision about participation. More discussion is needed about what competences a child needs to participate in court and to what extent this right should be limited by their age. Importantly, courts and decision‐making proceedings can be made more child friendly.