This exploratory case study examined the process and potential impact of collaborative architectural design and construction in an OpenSimulator-based virtual reality (VR) on the social skills development of children with high-functioning autism (HFA). Two children with a formal medical diagnosis of HFA and one typically developing peer, aged 8-11, were purposefully recruited and matched in a five-week, VR-based architectural design project. Participants' virtual behaviors and discourses were observed and archived via screen recording. We conducted qualitative time-series and micro-behavior analyses with the data collected. The findings demonstrated that VR-based collaborative design has awarded children with HFA an opportunity to practice and develop flexibility, identity, and norm construction. The target children's design-based social performance was mediated by the VR environment, the context or structure of design partnership, and the nature of a specific design task.