This article offers the first systematic analysis of the effects of domestic atrocity laws on human rights prosecutions. Scholars have identified various political and sociological factors to explain the striking rise in human rights prosecutions over the past 30 years, yet the role of domestic criminal law in enabling such prosecutions has largely been unexamined. That is surprising given that international legal prohibitions against human rights atrocities are designed to be enforced by domestic courts applying domestic criminal law. We argue that domestic criminal laws against genocide and crimes against humanity facilitate human rights prosecutions in post‐authoritarian states by helping to overcome formal legal roadblocks to prosecution, such as retroactivity, amnesties, immunities, and statutes of limitations. Using original data on domestic atrocity laws and human rights prosecutions in new democracies, we find that atrocity laws increase the speed with which new democracies pursue prosecutions, as well as the overall numbers of trials they initiate and complete.