In in-depth interviews with 25 Life Orientation teachers in South Africa, we found that teachers spontaneously drew upon notions of culture to explain and justify people's sexual beliefs and behaviours and their own role as educators. Drawing upon a Bakhtinian understanding of discourse, we apply critical semantic analysis to explore how culture is deployed as a discursive strategy. Teachers draw upon particular understandings of culture available to them in their social contexts. Furthermore, the substitution of the word ‘culture’ for a series of other phenomena (silence, violence and poverty) affords these phenomena a certain authority that they would otherwise not wield. We argue, first, that systems teacher education and training needs to (re)define culture as dynamic, interactive and responding to, but not determined by, socio-historical realities. Beyond this, teachers need to learn how to critically engage with cultural practices and perceptions and to be provided with some basic tools to do so, including more sophisticated understandings of cultural and training in dialogic methodologies. Teaching sexuality education in multicultural societies such as South Africa will require meaningful engagement in intercultural dialogues that may need to include voices that have traditionally been excluded from school spaces.