This paper combines considerations from ethics, medicine and public health policy to articulate and defend a systematic case for mask wearing mandates (MWM). The paper argues for two main claims of general interest in favour of MWM. First, MWM provide a more effective, just and fair way to tackle the ongoing COVID-19 pandemic than policy alternatives such as laissez-faire approaches, mask wearing recommendations and physical distancing measures. And second, the proffered objections against MWM may justify some exemptions for specific categories (...) of individuals, but do not cast doubt on the justifiability of these mandates. Hence, unless some novel decisive objections are put forward against MWM, governments should adopt MWM. (shrink)