Science, technology, engineering, and math (STEM) are approaches to help us to understand and improve the world. Therefore, as a country, we need to develop more STEM literate citizens through exemplary STEM learning in schools. This report asks four questions that are answered through five case studies: (1) What is exemplary STEM learning?; (2) What conditions support exemplary STEM learning?; (3) How does the collective leadership of teachers and administrators facilitate exemplary STEM learning?; and (4) What are the barriers to exemplary STEM learning? After analyzing survey data, interviews, focus groups, and site visits to five schools, this research found that schools with strong STEM cultures are more likely to improve by innovating to meet the needs of their students and communities. [This report was funded by 100Kin10. For the related report, "Exemplary STEM Learning: Lessons from Outstanding New York Schools & Teachers. Teacher Leader Fellowship Toolkit," see ED616151.]