Jeffrey David Sachs (born November 5, 1954, in Detroit, Michigan) is an American economist and Director of the Earth Institute at Columbia University. He is also 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. Also, he is Special Advisor to United Nations Secretary-General Ban Ki-Moon, and the founder and co-President of the Millennium Promise Alliance, a nonprofit organization dedicated to ending extreme poverty and hunger. 2002 to 2006, he was the Director of the United Nations Millennium Project Millennium Development Goals, eight internationally sanctioned objectives to reduce extreme poverty, hunger, and disease by the year 2015.

Originally one of the youngest economics professors in the history of Harvard University, Sachs became renowned for implementing economic shock therapy throughout the developing world, and subsequently for his work on the challenges of economic development, environmental sustainability, poverty alleviation, debt cancellation, and globalization. He has authored numerous books and articles on these subjects, including The End of Poverty and Common Wealth, both New York Times bestsellers. He has been named one of Time Magazine's "100 Most Influential People in the World" twice, in 2004 and 2005.

Sachs was raised in Oak Park, a suburb of Detroit, Michigan, and graduated from Oak Park High School. He attended Harvard College, where he received his B.A. summa cum laude in 1976. He went on to receive his M.A. and Ph.D. in economics from Harvard, and was invited to join the Harvard Society of Fellows while still a Harvard graduate student. In 1980, he joined the Harvard faculty as an Assistant Professor and was promoted to Associate Professor in 1982. A year later, at the age of 29, Sachs became a Full Professor of economics with tenure at Harvard.