Sergiu Hart (Hebrew: סרג'יו הרט) (born 1949) is an Israeli mathematician and economist.

thesis was on the subject of "Values of Mixed Games" and was supervised by Robert Aumann, who was also his advisor in his doctoral thesis on "Cooperative Game Theory Models of Economic Equilibrium" (Ph.D., summa cum laude, 1976).

Since 1991 he is a member of the Departments of Economics and Mathematics at the Hebrew University of Jerusalem, and he was the founding director of the Center for the Study of Rationality (1991–1999) there.

Among his major contributions are studies of strategic foundations of cooperation; strategic use of information in long-term interactions ("repeated games"); adaptive and evolutionary dynamics, particularly with boundedly rational agents; perfect economic competition and its relations to models of fair distribution; riskiness; forecasting and calibration; mechanism design with multiple goods.

Hart edited, with Robert J. Aumann, the first three volumes of the Handbook of Game Theory with Economic Applications (1992, 1994, 2002).

In 2012, he was invited to give the Algorithms, Combinatorics, and Optimization (ACO) Distinguished Lecture at Georgia Institute of Technology.

From 1991 to 2007, he became the member of the Academic Committee, Center for the Study of Rationality, The Hebrew University of Jerusalem.

From 2020, he became the member of the Academic Committee, Center for the Study of Rationality, The Hebrew University of Jerusalem.