Children have the right to participate in matters concerning them. The Swedish Child Welfare Services constitute an arena in which a significant portion of open care interventions for children and their families take place, and thus a context in which children’s participation should be realized. The overall aim of this licentiate thesis is to explore how child participation is constructed in interventions provided by Swedish Child Welfare Services. The study is based on social constructionist theory and includes semi structured interviews with 11 children aged 7-16, whom had experience of receiving open care interventions provided by Swedish Child Welfare Services over a period of time and focus group discussions with 14 family social workers who provide suchlike interventions. The data were analysed using Thematic Analysis. The first article, which has been published in a peer-review journal, is based on semi structured interviews with the children and focus group discussions with the family social workers. The article explores how child participation is constructed in interventions provided by Swedish Child Welfare Services and which elements are of importance to this process. The results suggest that child participation is a collaborative process in which both the child and the family social worker have an active role to play. Participation is done through a series of seemingly small, everyday actions by the child and the family social worker. By actively asking questions and allowing the child to practice participation and influence the process, the family social workers can, together with the child, work toward increased child participation in interventions. The second article explores children's actions of participation and how these can be understood in relation to situational constraints using the concept of agency. The article is based on the interviews with the children. The findings suggests that children's actions, as described by the children, are formed in relation to the context. Some actions of participation can be described as permissible and some, when children behave in a way that exceeds the boundaries permitted by their position as children, disturb the existing order. The results suggest there are situational constraints, such as limited range of options available to influence the intervention, limited access to apply for support and limited ways to find new solutions when the children are not satisfied with an intervention. The overall contribution of the study lies in the enhanced understanding of the collaborative process through which participation is done, as well as the increased knowledge of children’s actions of participation in a social work context.