Achim Steiner (born 17 May 1961) is an environmentalist, of Brazilian-German ancestry, who currently serves as the Administrator of the United Nations Development Programme.
Before joining UNDP, he was Executive Director of the United Nations Environment Programme UNEP (2006–2016), and director of the Oxford Martin School (2016–2017).
He has also served as Director General of the International Union for Conservation of Nature (IUCN) and Secretary-General of the World Commission on Dams.