School classes can be conceptualized as bounded communities of practice made up of teachers and students working together to build knowledge. Teachers make design decisions about physical and virtual spaces supported by information and communications technologies, and about curriculum. Design influences how students go about their work, and their learning outcomes, but its processes are rarely observed. This paper, based on observations and conversations in schools, explores how teachers engage in designing learning environments. It argues that while most teachers display leadership in design decisions for their classes, they should build on this experience to influence policy and become more involved in designing beyond the classroom walls. (Contains 4 figures.)