An interdisciplinary and pluralistic approach to teaching and learning has been proposed as one solution to the lack of a consensus definition of sustainable development (SD). For teachers, such an approach requires an awareness of the interconnections among different dimensions of SD and their underlying value-based assumptions. In this article, we investigate whether higher education teachers' conceptions of SD are consistent with these aims. We present the results of our interviews with five university teachers who are experienced in interdisciplinary SD in Finland. Our findings show that despite the teachers' rich conceptions of cultural sustainability, including a variety of topics, concepts and value questions, their understanding of economic sustainability is rather limited and sketchy. We suggest that universities support the teachers' social and peer learning based on reflections on unclear concepts and emerging SD ideas.