Jeffrey David Sachs, is an American economist, public policy analyst, and former director of the Earth Institute at Columbia University, where he holds the title of University Professor, the highest rank Columbia bestows on its faculty. He is known as one of the world's leading experts on economic development and the fight against poverty.

Sachs is the Quetelet Professor of Sustainable Development at Columbia's School of International and Public Affairs and a professor of health policy and management at Columbia's School of Public Health. As of 2017, he serves as special adviser to the United Nations (UN) Secretary-General António Guterres on the Sustainable Development Goals (SDGs), a set of 17 global goals adopted at a UN summit meeting in September 2015. He held the same position under the previous UN Secretary-General Ban Ki-Moon and prior to 2016 a similar advisory position related to the earlier Millennium Development Goals (MDGs), eight internationally sanctioned objectives to reduce extreme poverty, hunger and disease by the year 2015. In connection with the MDGs, he had first been appointed special adviser to the UN Secretary-General in 2002 during the term of Kofi Annan.

In 1995, Sachs became a member of the International Advisory Council of the Center for Social and Economic Research (CASE). He is co-founder and chief strategist of Millennium Promise Alliance, a nonprofit organization dedicated to ending extreme poverty and hunger. From 2002 to 2006, he was director of the United Nations Millennium Project's work on the MDGs. He is director of the UN Sustainable Development Solutions Network and co-editor of the World Happiness Report with John F. Helliwell and Richard Layard. In 2010, he became a commissioner for the Broadband Commission for Sustainable Development, whose stated aim is to boost the importance of broadband in international policy. Sachs has written several books and received many awards.