With the realities of climate change pressing in on us, sustainability discourse has gained currency, although some consider it to have been co-opted and emptied of meaning—′sustainababble′. This chapter reviews the state of sustainability education, including a brief update on the state of sustainability vis-à-vis climate challenges, the contested meanings of sustainability and the historical development of sustainability education particularly in relation to environmental education and the United Nations Decade of Education for Sustainable Development. The chapter ends with a glimpse into the polyarchy of learning edges in transformative sustainability education and the shift towards a relational ontoepistemology, creating conditions for a civilizational leap.