Ever since Education for Sustainable Development (ESD) was officially embedded in the Sustainable Development Goals in 2015, many assumed that ESD had arrived in formal education settings. In reality however, this is only true to quite a small degree. Its uptake within the UNECE region has been shown to be too slow. Seen in the context of the ever-growing challenges our societies – and especially young people within them – face, this article points to non-formal education (NFE) as a powerful driver of change towards sustainable development. It shows that NFE’s complementary power has been undervalued for too long, and its potential for youth participation has been left almost untapped. Three successful best practice examples from Austria deliver supporting evidence and show how to combine ESD and NFE from a policy implementation perspective. The article concludes that in reforming one-size-fits-all education systems, non-formal education for sustainable development should play a key part.