Maryam Mirzakhani (born May 3, 1977, Tehrān, Iran—died July 14, 2017, Palo Alto, California, U.S.) was an Iranian mathematician who became (2014) the first woman and the first Iranian to be awarded a Fields Medal. The citation for her award recognized “her outstanding contributions to the dynamics and geometry of Riemann surfaces and their moduli spaces.”

While a teenager, Mirzakhani won gold medals in the 1994 and 1995 International Mathematical Olympiads for high-school students, attaining a perfect score in 1995. In 1999 she received a B.Sc. degree in mathematics from the Sharif University of Technology in Tehrān. Five years later she earned a Ph.D. from Harvard University for her dissertation Simple Geodesics on Hyperbolic Surfaces and Volume of the Moduli Space of Curves. Mirzakhani served (2004–08) as a Clay Mathematics Institute research fellow and an assistant professor of mathematics at Princeton University. In 2008 she became a professor at Stanford University.

Mirzakhani’s work focused on the study of hyperbolic surfaces by means of their moduli spaces. In hyperbolic space, in contrast to normal Euclidean space, Euclid’s fifth postulate (that one and only one line parallel to a given line can pass through a fixed point) does not hold. In non-Euclidean hyperbolic space, an infinite number of parallel lines can pass through such a fixed point. The sum of the angles of a triangle in hyperbolic space is less than 180°. In such a curved space, the shortest path between two points is known as a geodesic. For example, on a sphere the geodesic is a great circle. Mirzakhani’s research involved calculating the number of a certain type of geodesic, called simple closed geodesics, on hyperbolic surfaces.

Her technique involved considering the moduli spaces of the surfaces. In this case the modulus space is a collection of all Riemann spaces that have a certain characteristic. Mirzakhani found that a property of the modulus space corresponds to the number of simple closed geodesics of the hyperbolic surface.