Four research projects used Second LifeTM, a 3D virtual-world platform, to investigate aspects of technology-enhanced STEM education. These European and USA studies, which differ in their pedagogical-philosophy commitments, theoretical frameworks, methodologies, and target content, critically examine a range of cognitive, affective, technical, and social factors pertaining to the prospects of students’ and teachers’ successful engagement with immersive microworlds. Specifically, each project describes students’ successes and challenges in creating complex virtual artifacts and collaborating in real time with peers and the broader community. The design-based research studies of mathematical and computational literacy present sample student artifacts and discuss the learning they evidence. Collectively, we posit that overcoming the following obstacles could make virtual worlds both effective and exciting learning environments: professional development (technical skill, affective disposition), collaboration with school systems (logistics of access, allocation of resources), alignment with targeted content (harnessing students’ creative divergence), and initial learning curves (issues of teacher-to-student ratio). Overview of Symposium Panel Recent technological developments have created opportunities for education researchers to evaluate the prospects of virtual worlds as arenas for facilitating STEM designs. Motivating factors for utilizing this new medium include its plasticity—it could potentially augment traditional learning environments by immersing learners in accessible reconstructions of real, confabulated, or hybrid loci that are remote in place, time, and/or scale, such as foreign lands complete with their geographical features, ancient archeological sites that come to life, sophisticated laboratories for safe handling of any contraptions and chemicals, microscopic organisms enlarged a million-fold, or galaxies reduced to neighborhoods. Yet as with any excitement created by “cool” technology, comes the sobering research-based acknowledgment that education practice must adapt prudently so as to assimilate the media in ways that best serve students. This symposium presents findings from a total of four European/USA research projects that study cognitive and affective factors contributing to students’ and teachers’ development of mathematical and computational literacy. Varying across participants, pedagogical commitments, theoretical frameworks, and methodology, the projects have in common a utilization and critical examination of the 3D virtual world as a medium for implementing designs for teaching and learning STEM content. Also, all of the learning environments were developed within the virtual worlds (Teen) Second Life (SL/TSL) (Linden Research, 2007). Finally, all projects seek to provide contexts that leverage students’ natural social inclinations, cater to a broad spectrum of initial capacity and idiosyncratic interests, position mathematics and/or computer-science content as conducive to the solution of suggested or emergent authentic problems, and provide formative-assessment infrastructure (cf. Barab, et al., 2007). Briefly, each project is described below: • Morgado and Esteves explore SL as a platform for teaching and learning introductory computer programming in Computer Science (CS) undergraduate courses. The main focus was transposing programming concepts and evaluating teacher and student needs by using an iterative action-research process. Morgado and Esteves describe how observations of unanticipated events led to parallel small-scale inquiry-based research efforts. • Veeragoudar Harrell and Abrahamson are conducting design-based research on critical-pedagogy frameworks, To appear in G. Kanselaar, J. van Merriënboer, P. Kirschner, & T. de Jong (Eds.), Proceedings of the International Conference of the Learning Sciences (ICLS 2008). Utrecht, The Netherlands: ICLS.