English learners (ELs) comprise a diverse and multitalented pool of learners that is persistently increasing, both in absolute size and as a percentage of the U.S. school population. ELs span more than 350 language groups, represent diversity in cultural groups, and reach the full range of social classes within U.S. society. Such diversity is at once a strength of the EL population and a complication to finding simple solutions to improving science, technology, engineering, and mathematics (STEM) outcomes for the group writ large. Long-held accounting practices in education and U.S. policy complicate the development of a clear picture of the educational attainment of ELs. Thus, high school graduation rates, college going, and career choices among ELs are misestimated in many official statistics and reports because of the failure to consider those Englishproficient students who began school as ELs. These facts notwithstanding, ELs are underrepresented in STEM fields in college as well as in the workforce. These lower participation rates are made more troublesome by the ever-increasing demand for workers and professionals in STEM fields and by the disproportionate economic value that these jobs bring to society and, as a result, to the individuals employed in STEM fields. In general, jobs in STEM fields have higher earning potential than non-STEM jobs, and the number of jobs in STEM have outpaced all other fields since 1990. Opening avenues to success in STEM for the nation’s ELs offers a path to improved earning potential, income security, and economic opportunity for these students and their families. At least as important, increasing the diversity of the STEM workforce confers benefits to the society as a whole, not only due to the improved economic circumstances stances for a substantial segment of society, but also because diversity in the STEM workforce will bring new ideas and new solutions to STEM challenges. Organizing schools and preparing teachers so that all students can reach their full potential in STEM has the potential to transform the lives of individual students, as well as the lives of the teachers, the schools, and society as a whole. In the report that follows, the committee attempts to determine what can be learned from the research literature to help guide improvements in the educational system, through improved assessments and assessment practices; reporting and classification; improved instruction that recognizes the central role that content area instruction plays in children’s language development and content area achievement; leveraging connections to home, culture, and school; better preparation of teachers and administrators; and the establishment of federal, state, and local policies that will build and sustain capacity of school systems to allow all ELs to reach their full potential as STEM learners.