Sidney Graham Winter (born 1935, in Iowa City, Iowa) is an American economist and Professor Emeritus of Management at the Wharton School, University of Pennsylvania. He is recognized as a leading figure in the revival of evolutionary economics.

In 1982, he co-published with Richard R. Nelson An Evolutionary Theory of Economic Change, a book which has since been cited nearly 25,000 times.

Winter was Chief Economist of the US General Accounting Office (1989-1993). He won the Viipuri Prize for Strategic Management in 2008.

Winter was the second husband and widower of economist Alice Mitchell Rivlin.