This article explores and analyses the context of school-based teacher development in Sub-Saharan Africa. The argument is made that many aspects of the teacher problem in these regions mirror those in the rest of the world, but the size and scale of the need makes the challenge of providing schools and teachers to achieve "Education for All" (EFA) one of the world's biggest educational problems. As such, a response from the global community, parallel to similar initiatives in health, is required. The context of the problem is set out, particularly the inevitability of creating new school-based modes of teacher development. The analysis draws extensively on the work of the Teacher Education in Sub-Saharan Africa (TESSA) research programme. The article then goes on to suggest: (1) the revolution in communication technologies provides an opportunity radically to reassess the forms and modes of teacher development, particularly in rural areas; and (2) there is a need for research and development activity to provide the foundation upon which such potential can be realized. In this context a new "architecture for teacher development" needs putting in place, a process that should be a mainstream concern for the world's education research community.