The COVID-19 pandemic has caused major disruptions to U.S. school systems since March 2020. To facilitate our understanding of how school nurses participated in school reopening and what support school nurses needed beginning the 2020–2021 school year during the COVID-19 pandemic, we conducted a national survey in late summer 2020. A sample of 747 school nurses from 43 states responded to an online survey about roles, practices, and concerns. Over one-third (36.9%) reported not being included in school reopening planning. Mitigation practices reported by respondents primarily included measuring temperatures of students before school (21.3%), mask wearing by students (79.9%), and 6 feet social distancing (76.7%). The respondents’ greatest concerns were the educational impact on students with individualized education plans, parents sending children to school with COVID-19 symptoms, and the economic impact on families. Our results point to opportunities for greater school nurse involvement, improvements in practices, and measures to address school nurses’ concerns.