A contest is a situation in which individuals expend irretrievable resources to win valuable prize(s). “Sabotage” is a deliberate and costly act of damaging a rival’s likelihood of winning the contest. Sabotage can be observed in, e.g., sports, war, promotion tournaments, and political or marketing campaigns. In this article, we provide a model of, and different perspectives on, such sabotage activities and review the economics literature analyzing the act of sabotage in contests. We discuss the theories and evidence emphasizing the means of sabotage, why sabotage occurs, and the effects of sabotage on individual contestants and on overall welfare, with possible means of reducing sabotage. We note that most sabotage activities are aimed at the ablest contestant, the possibility of sabotage reduces productive effort exerted by the contestants, and sabotage may lessen the effectiveness of public policies, such as affirmative action, or information revelation in contests. We discuss the different policies a designer might use to counteract sabotage. We conclude by pointing out some areas of future research.