Sustainable development is one of the most influential concepts in contemporary international policy. The talk traces the origins of this ubiquitous yet elusive notion in the 1970s and 1980s, discussing specifically the ideas of the two women who are credited with its invention, Barbara Ward and Gro Harlem Brundtland: how they imagined sustainable development as the pillar of a new, post-Cold War international order, how they problematised growth and social justice, and how they envisioned a special responsibility of Europe/the European Community in promoting it.