Criminal groups often avoid the limelight, shunning publicity. However, in some instances, they overtly communicate, such as with banners or signs. This article explains the competition dynamics behind public criminal communication and provides theory and evidence of the conditions under which it emerges. Relying on a new dataset of approximately 1,800 banners publicly deployed by Mexican criminal groups from 2007 to 2010, the study identifies the conditions behind such messaging. The findings suggest that criminal groups “go public” in the presence of interorganizational contestation, violence from authorities, antagonism toward the local media, local demand for drugs, and local drug production. Some of these factors are associated only with communication toward particular audiences: rivals, the state, or the public. An interesting finding is that the correlates of criminal propaganda are sometimes distinct from those of criminal violence, suggesting that these phenomena are explained by separate dynamics.