This book-length study explores the discursive construction of pregnant migrants in Ireland as paradigmatic figures of illegal immigration; the measures that were taken in response; and the cultural, social, and economic consequences of these developments for migrants and citizens. It argues that these Irish transformations drew on and contributed to similar transformations globally, including in the United States, where controversies over pregnant migrants legitimized legal changes that rendered increasing numbers of migrants “illegal,” reconfigured multiple social hierarchies—and generated resistance. The study brings the scholarship on the social construction of illegal immigration into critical dialogue with queer theory. Immigration scholarship shows that designations of legality and illegality do not reflect individual character, but instead, stem from histories of colonialism, global capitalism, racism, and nation-building. The role of sexual regimes in shaping immigrants’ legal status designations remains overlooked, however. By using queer theory to analyze how pregnant women became constructed as illegal immigrants, this project fills that gap in immigration scholarship. The project also expands queer theory by exploring how crises over illegal immigration transform nationalist sexual norms and associated social hierarchies at interlinked local, national, and global scales.