Through an ethnographic study that took place in highly diverse primary school classrooms in London and the East of England, UK, this book engages with teachers' perspectives and children's descriptions of their plurilingual experiences, as it explores what constitutes, hinders and potentially facilitates teachers' agency in multilingual pedagogies. The concept of teacher agency offers a powerful lens for critical reflections on the -- often monolingual -- status quo and on possible transformations in schools, where teachers seek to create pedagogical spaces that acknowledge, engage and promote pupils' plurilingual repertoires. This book develops a nuanced framework for understanding and enhancing teacher agency in multilingual pedagogies. It also encourages teacher educators and policymakers to recognise multilingual pedagogies as an integral part of (primary) school pedagogy and to support the capacity of present and future teachers to build on their professional knowledge and experiences, when normalising multilingual pedagogies in mainstream schools.