This book examines how informal learning pedagogy is understood, implemented and experienced in music education. It highlights the benefits and challenges facing the approach in practice, over twenty years after Lucy Green's seminal How Popular Musicians Learn first established these ideas. The book draws on two research projects that trace the development and evolution of informal learning. The first project comprised in-depth case studies of secondary schools implementing informal learning pedagogy in England, and drew interview data from three key figures who played a pivotal role in establishing, disseminating and promoting that pedagogy. The second project interviewed with music teachers who facilitate informal learning across primary, secondary and international contexts. Increasing student choice and autonomy, boosting student motivation and widening participation and inclusion, informal learning is a valuable approach across international contexts. This book draws attention to some of the barriers and enablers of this value in practice, offering implications for practice and policy to ensure the future sustainability of the approach.