This article examines recent educational reforms in Tanzania by looking at the cultural politics of pedagogical change in secondary and teacher education. It presents an ethnography of a teachers college founded on the principles of social constructivism in a country where formalistic, teacher-centered pedagogy is the norm. Using data collected through a year of participant observation, it argues that the cultural, economic, and political dimensions of teachers' practice need to be considered alongside efforts to reform the country's educational system. It offers contingent constructivism as an alternative to the international consensus on a single model of excellent teaching.