Journalists, scholars, and citizens have raised concerns regarding the high share of incivility in comment sections of news outlets. The current study surveyed members of the social movement #ichbinhier, which aims at collectively countering uncivil comments to cultivate a civil discussion atmosphere in comment sections. We root the activities of #ichbinhier as corrective action and identify the determinants of the members’ engagement by integrating research on bystander behavior and collective action. The findings of our survey show that factors pertaining to individual skills, perceived responsibility, and expected benefits relate to the members’ likelihood to engage against uncivil online comments. Regarding factors derived from collective action research, group efficacy and knowledge of the rules and structures of the movement account for higher levels of engagement. These results shed light on the factors that motivate and inhibit #ichbinhier members—and, potentially, Facebook users in general—to engage against uncivil comments.