This entry sketches the relation between knowledge generation (KG) and sustainable development (SD) as it appears within the realm of Higher Education for Sustainable Development (HESD). The suggestion is to distinguish three forms of appearances: The first relation can be called a passive relation. In this appearance, KG for SD is mainly undertaken by (academic) experts whose results and methods are conveyed to students in forms of canonical knowledge within HESD. The students’ role in KG processes is hence the role of passive recipients of this canonical knowledge. Opposed to this appearance is the active relation. Here, students (and other social actors) are directly included in the process of KG in order to craft applicable solutions to concrete challenges for SD. Moreover, KG is not restricted to the acquisition of explicit knowledge. It also includes the development of tacit forms of knowledge that are deemed important for the prospective professional activities of students. Nevertheless, both the passive and active relation share an external orientation of KG processes, meaning that their matter of interest is neither the participants themselves nor the way they produce new knowledge. The third appearance, in contrast, primarily construes KG as a subjective process in which new information concerning SD is translated into new knowledge representations. It can be called reflexive appearance, because it aims to obtain awareness of the subjective process of KG, thereby laying the grounds for constructive KG processes for SD in the passive and active sense.