This book argues that post-truth discourses are deeply influencing political debates on migration and border security, blurring the line between fact-based debates and post-truth storylines. Offering a nuanced analysis of discourse within parliamentary debates on migration across multiple EU countries and the European Parliament, the book challenges conventional assumptions about the drivers of post-truth, highlighting its role in legislative settings rather than solely in informalised public fora like social media. It illuminates the presence and use of post-truth narratives and the pervasiveness of post-factual politics at the centre of democratic policy-making processes, namely parliamentary debates, and highlights how certain post-truth structures become embedded into mainstream political debates and policies. This book will be of key interest to scholars, students and professionals in migration policy/studies, political communication, communication studies, and more broadly to public policy, European studies, media studies, international relations and sociology.