In theory, terrorism is a political communication strategy for groups to convey their grievances and the costs of ignoring them. In practice, though, terrorist groups take responsibility for just a small portion of their attacks. Rather than getting credit for the violence, terrorist leaders generally deny their operatives committed it. This theoretical and empirical disconnect may explain why scholars have ignored the subject of unclaimed attacks despite these being the norm. With a mixed-methods research design, our study helps to fill this lacuna by proposing and testing a new theory to help account for variation in which attacks are claimed.