Beyond the reaches of scholarly debates about how to define and value civility properly, social actors across various institutional domains routinely demarcate civil from uncivil behavior. Yet this everyday classification process remains understudied and undertheorized, despite being widespread and having significant stakes for the individuals and groups involved. This article begins to fill this gap by developing the concept of civility contests—practical efforts to draw symbolic boundaries between civil and uncivil individuals, groups, or behaviors. Through a focus on the realm of political protest in the United States, this article demonstrates that civility contests involve a wide range of political actors (including institutionalized power holders, opposing movements, and the media) who engage in this boundary-work in order to justify the control or (de)legitimation of protest. It then highlights patterned disparities in the outcomes of these contests, demonstrating that the likelihood of being marked as uncivil and the extent to which this prompts negative social sanction is shaped by one’s social position. Overall, the article seeks to stimulate and guide future empirical research on civility contests and to deepen theoretical understandings of the relationship between symbolic and social boundaries and the role of symbolic boundary-work in the reproduction of political inequality.