This book examines teachers’ beliefs, attitudes, and knowledge regarding multilingualism and linguistic diversity in Dutch primary education. Drawing on extensive empirical research, it analyses how teachers interpret and justify their everyday classroom practices within broader institutional and ideological contexts. Moving beyond individual-level explanations, the book conceptualises teachers as institutional actors whose professional judgments are shaped by accountability systems, dominant language ideologies, and enduring assumptions about language, learning, and social integration. While many teachers express inclusive values and a strong commitment to students’ well-being, the findings demonstrate how multilingualism is often positioned as educationally irrelevant or potentially problematic within monolingual norms. The analysis shows that minority languages are not explicitly rejected but are systematically marginalised by routine pedagogical reasoning, thereby contributing to the persistence of deficit perspectives in education. By identifying the structural conditions underpinning these patterns, the book advances current debates on multilingual education and language policy. This volume will be of interest to educators, researchers, graduate students, and policymakers working in the fields of multilingual education, sociolinguistics, teacher education, and educational policy.