Much of the national attention on science, technology, engineering, and mathematics (STEM) education tends to concentrate on science and mathematics, with its emphasis on standardized test scores. However as the National Academy of Engineering Committee on K-12 Engineering Education stressed, engineering can contribute to the development of an effective and interconnected STEM education system. In addition, engineering can provide authentic learning contexts for science, technology, and mathematics. Numerous K-12 engineering initiatives have emerged across the U.S. developing curriculum and conducting teacher professional development. The focus of pre-college engineering education has largely been on process, with engineering content or concepts playing at best a secondary role. Within teacher professional development this lack of focus on engineering concepts is also evident. One key problem confronting engineering professional development observed by Daugherty (2009) in a multiple case study project is the lack of a well-defined concept base. The findings from the individual case studies were compared and summarized across the study's research questions, which included a focus on identifying the fundamental content knowledge. As evidenced by the case studies, engineering content is not well-defined for secondary level education. The projects' leaders, instructors, and participating teachers discussed engineering in terms of the design process and were unable to articulate the associated content or concepts. This void poses serious problems for curriculum and professional development, as well as for research. In the absence of a conceptual base, materials tend to focus solely on design-based activities, lacking a focus on conceptual learning. In order to address this gap Custer, Daugherty, and Meyer (in press), in a study funded by NCETE, identified thirteen engineering concepts deemed to be core to engineering and appropriate for the secondary level. To further this effort beyond a list of thirteen concepts, the current study, also funded by NCETE, convened a focus group comprised of pre-college engineering education, cognitive science, and/or concept mapping experts to discuss how and in what ways concept mapping could be used in secondary level engineering education. The study's research questions were: (1) How can concept mapping be used to facilitate learning in secondary level engineering education?; (2) How can concept mapping be used to assess learning in secondary level engineering education? (Contains 2 figures and 3 tables.)