In this paper we raise serious concerns about existing case-study research on sustainability in higher education. Our key concern is that the research does not live up to its potential for improving the field of sustainability in higher education. We have argued that case-study research in the field falls short of its promise due to a lack of theorizing about the research methodology or an understanding about the methodology. If case-study research is to lead to an improvement in the way universities respond to sustainability in their curriculum, activities, policies and functions then researchers need to address the manner in which they conduct and report their research. Based on an analysis of 54 journal articles on sustainability in higher education, four areas of concern have been identified. The paper converges in a set of critical considerations for conducting case-study research in sustainability in higher education.