This book introduces a new framework for understanding how the radical right reimagines demographic change as an existential threat. Across Europe and the Americas, low birth rates, immigration, and gender equality are reframed as signs of civilisational decline. This volume explores how radical right actors mobilise fears around fertility, migration, race, family, and sexuality through narratives of crisis, ethnic purity, and control over borders, reproduction, and social norms. It examines conspiracy thinking fuelled by demographic anxiety to justify attacks on gender and sexual rights and reinforce exclusionary ideas of national belonging. Grounded in empirical case studies and interdisciplinary approaches, this book reveals how these narratives converge to reinforce dominance of a native, heteronormative, Christian population. In linking domains often treated separately, it provides a timely and critical perspective on the evolving logic of radical right politics worldwide.