Since 1994, the democratic South African government has introduced change in all spheres of South African life in a bid to address some challenges such as the redundant, racialised curriculum, the poor results achieved by learners in Grade 12, and the fact that few black matriculants were entering science based careers. A key feature of these poor results was the large group of teachers who were inadequately "trained" during the apartheid era: trained, that is, to teach for subservience and not for critical thinking. Current actions to address this crisis are being undertaken in a collaborative relationship between the Department of Education and Higher Education Institutions. Current initiatives in the professional development of Mathematics, Science and Technology teachers at a South African university are explored. The purpose of this article is to explore the challenges of designing an MST professional development programme in a developing context. The discussion is elaborated with reference to MST programmes run by one particular university. The rationale, foundational principles, model of delivery, programme structure and assessment for the specialisations within the teacher professional development programmes at the university are described. The discussion foregrounds the role of teachers as professionals, the role of context and of content knowledge, as well as the role of pedagogic content knowledge in the professional development of teachers.