We explore the question of how child designers can provide design ideas for technology that might reduce the marginali- sation that can be experienced by some of their peers. To do this, we introduce the idea of Expanded Proxy Design that moves beyond the notion of “proxies as people” in design, to guide methods for engaging children into thinking about design ideas for a group that exists at some distance from their own experience. We outline three case studies where we made use of such methods. First, we consider expanded proxies in the context of technology and newly immigrant children who are unable to speak in English. Second, we consider the case of designing technology for children with and without visual impairments. Finally, we consider designing playful experi- ences for children with different temperaments. We reflect on the extent to which this expanded notion of proxies can be used as a meaningful vehicle for overcoming marginalisation and exclusion when children with different abilities design for each other. And we suggest ways to characterise, develop and refine expanded proxy design methods in this broader sense.