The purpose of the study was to identify and refine a conceptual foundation for secondary school engineering education. Specifically, this study sought to address the following research questions: (1) What engineering concepts are present in literature related to the nature and philosophy of engineering?; (2) What engineering concepts are embedded in secondary level science, technology, engineering, and mathematics standards? (3) What engineering concepts are embedded in secondary level engineering-oriented curriculum?; (4) What engineering concepts have been identified in the related research literature?; and (5) What engineering concepts are deemed core for secondary level education by practicing engineers and engineering educators? Key input activities included conducting a review and synthesis of extant educational materials focused primarily on standards, curriculum materials, and various research studies. In addition to these materials, literature from the history and philosophy of engineering was also reviewed and included in the analysis. Also included in the process was a series of focus groups sessions conducted with selected engineering educators and practicing engineers to identify and classify their recommendations of concepts appropriate for secondary level engineering. As a final phase of the process, a reaction panel of engineering and technology education experts was convened. (Contains 1 table.)