As virtual worlds for children increase in popularity, it is important to examine their developmental implications. Given the limited research on this question, we use extant social science research on youth and digital media to understand how children 's participation in virtual worlds might mediate their development. We identify four different pathways by which new media can potentially mediate development. Then we review relevant research on video games, which, like virtual worlds, contain three-dimensional online fantasy worlds; we also review research on online communication forums, which are like virtual worlds in that they allow users to create online selves and interact with one another. These studies also provide concrete examples of the pathways by which media influence development. We examine three specific questions about children 's use of virtual worlds: what they typically do in them, their learning potential, and whether virtual world participation mediates development. We conclude that children's virtual world activities resemble their offline ones, indicating that their offline and online worlds may be connected. The potentialforl earningf rom virtual worldp articipationi s as yet unknown and requires further research. Children's online selves are connected to their offline ones and this has implications for their safety; although their interactions in virtual worlds appear to mirror offline patterns, we do not as yet know their potential benefits or costs. The Article concludes that although children's virtual world activities and interactions may be connected to their offline lives, there are several pressing questions about their participation that must be addressed.