This study presents selective moral disengagement as a paradigm for analyzing extremist marketing messages and developing effective countermessages. Selective moral disengagement explicates eight mechanisms common to extremist media content that can influence seemingly ordinary people to support and commit atrocities. Through a qualitative content analysis, the author investigates the use of moral disengagement mechanisms in an online propaganda magazine (Rumiyah) of the so-called Islamic State (IS) terrorist organization. This article demonstrates the extensive use of the eight moral disengagement mechanisms throughout a variety of genres of IS propaganda articles. In addition, a ninth moral disengagement strategy—humanization of perpetrators—emerged. The analysis reveals internal inconsistencies in IS’s approach to moral disengagement. The author argues that careful consideration of the use of these mechanisms in IS propaganda clarifies the understanding of IS’s marketing strategy and informs countermessaging efforts. Specific countermessaging approaches are proposed for combatting IS given these findings. Further, a roadmap is given for extending the selective moral disengagement analysis paradigm into other extremist marketing contexts, including U.S. domestic terrorism.