Explaining the drivers of compliance with international law has been a central concern of international lawyers (and many others) for decades. As international agreements have proliferated—exact numbers are elusive, but there may be 75,000 or more—understanding compliance has only grown in importance. In previous work we each have explored the question of compliance, focusing on the conceptual difficulties with compliance as a measure of effectiveness, the role of reputation, and other factors. The literature on compliance with international law is rich, interdisciplinary, and, at this point, over three decades old. In Rewarding in International Law, Anne van Aaken and Betül Simsek seek to offer a new perspective on the enduring topic of compliance: that of rewarding. In this essay, we suggest that rewards, when properly defined, are a conceptually interesting but empirically rare tool in the arsenal of states seeking to improve compliance with international law.