High Reliability Organisations (HROs) operate in complex, high-risk environments where accidents might be expected to occur frequently, but they actually have fewer than might be expected. However, recent thinking suggests that what defines a HRO is not safety or reliability performance, but how it thinks and acts. The key is that HROs anticipate the unexpected AND contain the unexpected when it occurs. The current COVID-19 pandemic has highlighted the importance of the best practices of the HRO approach. This article outlines the five key characteristics of HROs in order to help organisations respond to the COVID-19 pandemic and other future unexpected events.