Is targeted killing an effective counterterrorism tactic? Several studies published in academic journals over the last decade differ over the answer. While some believe that it is effective as a tactic within a larger counterterrorism strategy, others believe that it has no effect or possibly a negative effect in countering terrorism. This paper argues that although current studies may be valuable for understanding the impact of targeted killing in specific case studies, they do not yet provide a basis for making general pronouncements on whether targeted killing is or is not an effective counterterrorism tactic. Problems include widely divergent definitions, a dearth of evidence, difficulties in measuring success, and the radical differences between case studies that make comparison and generalization a questionable exercise. However, while the evidence does not yet allow scholars, pundits, and policymakers to make general pronouncements on the effectiveness of targeted killing generally, it does provide grounds to begin a normative debate over whether such policies are appropriate. In addition, it suggests that researchers and policymakers should focus on gathering and improving empirical data to advance decision making on counterterrorism tactics in the future, particularly on when targeted killing should or should not be employed.