With the ever-growing imperative of sustainability, there is an increasing need for capable graduates who can address the wicked problems of sustainability. This research examined undergraduate tourism students' understanding of the concept of sustainability before and after participating in an undergraduate sustainable tourism course. Prior to the course, students had simple stereotypical conceptions of sustainability. Whereas after the course they had an enhanced relational understanding of the triple bottom line as well as community and social dimensions of sustainability. Learner-centred critical and transformative approaches are important in facilitating the development of more complex ways of thinking about sustainability.