This paper examines two key concepts in educational paradigms - knowledge and competence - from the perspective of their importance for a sustainable society. It is argued that knowledge should not be considered as something existing that is to be acquired, but rather as part of a knowledge-building process that poses questions regarding why we build knowledge and what kind of knowledge we build, as well as how we build it and how we use it. Knowledge building is also considered a type of competence in an endeavour to go beyond current models that tend to see competence as merely the application of knowledge and fail to do justice to the role of both in promoting sustainability