Masks are coverings of the face that serve a variety of purposes. Throughout history, they have been used for religious ceremonies, theatric entertainment, protection of identity, and as a tool to limit the spread of infectious diseases. The development of masks in the medical setting has evolved along with our understanding of the mode of disease transmission, material science, and population health dynamics. The simple barrier face mask, surgical mask, and filtering facepiece respirator are each appropriate in different settings. Establishing evidence-based guidance behind the use of masks is essential, particularly in public health crises.