Opportunities to learn about science, technology, engineering, and mathematics (STEM) are all around. Yet, people often assume that formal school settings are the only places to learn about the STEM disciplines. A consensus report from The National Academies, Learning Science in Informal Environments: People, Places and Pursuits (NRC, 2009), helped to upend this assumption and galvanized over a decade of expansion in programming and research focused on informal STEM learning. In the years since publication of the 2009 report, opportunities to learn science and STEM more broadly in informal environments have greatly expanded and they now serve as an essential component of STEM education and engagement across the country. In parallel with the expansion of programs, research on all aspects of STEM learning has continued to progress, offering new insights into how to improve people's STEM learning in all settings. Given this tremendous growth, the new insights generated by advances in research, and the considerable changes wrought by the COVID-19 pandemic the time is ripe for taking stock of the past 15 years of work. This new consensus study will update the 2009 report to codify what is currently known about how to best support learning across informal STEM environments, thus laying the groundwork for effective decision-making in practice, policy, and research in the field. The report will help to identify gaps for where additional programming in informal STEM education would b