Experience from the fall 2020 semester suggests that fast, frequent testing can help mitigate the spread of COVID-19 in a large and diverse university community, but it must also be emphasized that testing is only one component of a coherent mitigation strategy. A comprehensive approach requires the application of epidemiology and science; rapid isolation of positive individuals and quarantine of those with potential exposures; contact tracing; environmental management; mask wearing; physical distancing; and engagement with the community, particularly local public health officials. This rapid expert consultation summarizes what is known to be effective with respect to testing strategies for college and university campus reopening, including the types of diagnostic testing employed, testing frequency and targets, metrics typically reported, responses to positive tests, and efforts to ensure compliance. The Societal Experts Action Network (SEAN) is an activity of the National Academies of Sciences, Engineering, and Medicine that is sponsored by the National Science Foundation. SEAN links researchers in the social, behavioral, and economic sciences with decision makers to respond to policy questions arising from the COVID-19 pandemic. This project is affiliated with the National Academies' Standing Committee on Emerging Infectious Diseases and 21st Century Health Threats.