This article reviews the remarkable growth in empirical literature in political science on wartime sexual violence against civilians, including rape, sexual slavery, forced marriage, and other forms. Early work, motivated by ongoing conflicts in the former Yugoslavia and Rwanda, tended to portray these forms of violence as inevitable, ubiquitous, and either opportunistic or strategic. However, recent literature and new data sources have documented substantial variation in sexual violence across countries, conflicts, perpetrators, and victims and survivors. Building on this observed variation, scholars have developed and tested a wealth of theories about when, where, why, and under what conditions sexual violence occurs as well as its consequences. We highlight the core findings from the literature, explain the key debates among experts, and explore several avenues for future research. We conclude by detailing what the study of wartime sexual violence—both the findings and the research process—offers to a broader set of political science scholars.