Progress on the Sustainable Development Goals (SDGs) depends, in part, on the sustainability competencies of professionals in various fields, and thus, on the implementation of sustainability curricula in higher education. While many universities now offer sustainability curricula, and many more aspire to, there is a lack of evidence on what supports or hinders such implementation. This article presents a meta-study on 133 case studies from universities around the world and synthesizes the main drivers and barriers, identifies information gaps, and tests prominent assumptions on implementing sustainability curricula in higher education. The findings confirm that such implementation is associated with strong leadership by the university; incentives and support through professional development; concurrent implementation of sustainability in research, campus operations, and outreach; formal involvement of internal and external stakeholders as well as sustainability champions, among others. Common research protocols for case studies are needed to yield comparable data on these influencing variables and to enhance reliability of cross-case comparisons. Most sustainability programs could utilize the findings for informing their implementation processes.