In Canada, as in other industrialized welfare states, definitions of health system sustainability reflect different goals and correspondingly diverse ways of understanding exactly what is to be sustained and how. In this article, we report on results from a survey of documents and groups involved in and/or concerned about sustainability of the healthcare system. We identify four broad narratives of sustainability in Canadian healthcare reform discourse, and explore what these different sustainability narratives tell us about the character and contours of these often-fractious debates. We argue that sustainability itself may not be a paradigm shift, as has been suggested, but a plot device that helps to steer the story in a particular direction, ‘black-boxing’ certain aspects of context and emphasizing others.