In this response article, we explain why sustainability issues are often interpreted as 'wicked' or unstructured problems and focus on the consequences for education and societal transformation in view of sustainable development. Drawing on Funtowicz and Ravetz' (1993) fourfold 'facts are uncertain, values in dispute, stakes high and decisions urgent' we analyse how the different articles of this special issue tackle the 'post-normal' characteristics of sustainability issues. To stimulate the interdisciplinary dialogue and put forward an open concept that can serve as a helpful framework for research collaborations and/on educational practices, we put forward three maxims of 'post-normal education' (PNE). Like Funtowicz and Ravetz, who highlighted the specificity of post-normal science, we put the specificity of PNE on the agenda, and more in particular, we stress the need to balance the urgency and the wickedness of sustainability issues.