Advocates of more connected approaches to teaching the STEM subjects argue that such integration, especially in the context of real-world issues, can make these fields more relevant to students and ultimately increase their motivation and achievement. However, there is little research on how best to integrate the STEM disciplines or on what factors make integration more likely to produce positive outcomes. This article summarizes the results of a recent study of STEM integration in K-12 education by the National Academies of Sciences, Engineering, and Medicine. The study reviewed evidence on student outcomes, developed a descriptive framework for practitioners, suggested key elements for the design of integrated STEM initiatives, and identified research priorities. The report from the study provides a useful foundation for future efforts to implement effective integrated STEM education.