This chapter describes the major research findings from empirical research on pre-college students’ and teachers’ learning of nanoscale science, engineering, and technology (NSET) concepts, organized in terms of the following big ideas: size and scale; structure of matter; size-dependent properties; forces and interactions; self-assembly; tools and instrumentation; models and simulations; and science, technology, and society. The big idea that has received the greatest attention in NSET learning-related research is size and scale. Individuals tend to systematically misjudge the sizes of objects larger or smaller than themselves as bigger or smaller than they actually are, although not with the same degree of difficulty relative to the human scale. The ways in which individuals conceptualize size and scale may also be mediated by factors related to cultural influences and learning environments. Teachers undeniably play a pivotal role in the integration of contemporary, cutting-edge science in the pre-college classroom.