Human action is not rational, and this irrationality manifests itself especially in decisions under uncertainty – the COVID-19 pandemic is one example of many in this respect. At the same time, various branches of research have been able to identify systematic patterns in irrational human behavior, and these have been attempted to be subsumed under the umbrella term of 'nudging'. Nudging describes the intentional change of decision architectures with the purpose of transforming irrationalities and/or distortions of human perception into predictable action. Thus, nudging represents a potent communication tool, especially in crisis communication scenarios. After presenting the basic theoretical assumptions of nudging, two examples of highly effective crisis communication strategies employed during the COVID-19 pandemic will be used to illustrate, contextualize, and reflect on central mechanisms and workings of nudging. This chapter ends with a summary of the most central findings as well as a critical reflection on potential future fields of action.