Sy-David Friedman (born May 23, 1953, in Chicago) is an American and Austrian mathematician and a (retired) professor of mathematics at the University of Vienna and the former director of the Kurt Gödel Research Center for Mathematical Logic.

He studied at Northwestern University and, from 1970, at the Massachusetts Institute of Technology.

He received his Ph.D. in 1976 from MIT (his thesis Recursion on Inadmissible Ordinals was written under the supervision of Gerald E. Sacks).

In 1979, Sy Friedman accepted a position at MIT, and in 1990 he became a full professor there.

Since 1999, he has been a professor of mathematical logic at the University of Vienna, and he retired in 2018.