Children are usually more competent than acknowledged by adults and designers. Valuable user perspectives are lost if only information from adult carers such as teachers and parents is included in the design process. Participatory projects can be empowering processes resulting in empowered outcomes, i.e. increased physical empowerment of children and products that raise their quality of life. In this paper, a theoretical platform for developing a design methodology for participatory design with underprivileged children in developing countries is presented. The framework consists of an explanation of psychological empowerment in the context of participatory design processes, a definition of participatory design with children, and a model distinguishing between different levels of user participation. Experiences and results from a case study conducted with children using prosthetic legs in Cambodia are described. The case study shows that through simple participatory techniques, children can give designers insight into their needs and desires.