This book explores why and how ethnonational minorities - specifically Roma, Hungarians, and Muslims in Central and Southeastern Europe (CSEE) - engage in legal mobilisation.This groundbreaking volume examines the legal mobilisation of ethnonational minorities CSEE amid growing challenges to democracy and minority protection. While the region has experienced multiple waves of minority rights regimes - from post-World War I treaties to post-1989 European integration - suspicion toward minorities’ perceived “dual loyalties” has endured.Focusing on three key groups rooted in the former Austro-Hungarian and Ottoman Empires - Hungarian minorities in states surrounding Hungary, the Roma across the region, and Muslims in the Balkans - the book explores how these communities harness the law to assert their rights under increasingly hostile conditions. Through detailed case studies of legal advocacy, grassroots legal activism, and strategic litigation, it illuminates the diverse ways minorities engage with national and transnational legal frameworks to secure recognition, resist discrimination, and shape political agendas.By comparing their strategies over time, the volume uncovers how legal action intersects with political and community mobilisation, showing how minorities adapt to shifting contexts; from the relatively open, EU-driven environment of the 1990s and 2000s to today’s more restrictive, illiberal regimes.Through its naunced analysis, this book will appeal to scholars and practitioners of minority rights, legal mobilisation, European politics, and socio-legal studies. It provides essential insights into how marginalised groups continue to fight for justice through law, even as the rule of law itself comes under threat.