Benson Stanley Farb (born October 25, 1967) is an American mathematician at the University of Chicago. His research fields include geometric group theory and low-dimensional topology.

A native of Norristown, Pennsylvania, Farb earned his bachelor's degree from Cornell University.^{[citation needed]} In 1994, he obtained his doctorate from Princeton University, under supervision of William Thurston.^[1]

Farb has advised over 40 students, including Pallavi Dani, Kathryn Mann, Dan Margalit, Karin Melnick and Andrew Putman.^[1]

In 2012 Farb became a fellow of the American Mathematical Society.^[2] In 2014 he was an invited speaker at the International Congress of Mathematicians in Seoul, speaking in the section on Topology.^[3] He was elected to the American Academy of Arts and Sciences in 2021.^[4] In 2024 he was awarded the Leroy P. Steele Prize for Mathematical Exposition.^[5]

• Benson Farb; Dan Margalit (2012). A Primer on Mapping Class Groups. Princeton University Press. ISBN 978-0-691-14794-9. MR 2850125.^[6]
• Farb, Benson; Dennis, R. Keith (1993). Noncommutative Algebra. Springer-Verlag. ISBN 978-1-4612-0889-1. MR 1233388.

Farb married Amie Wilkinson, professor of mathematics at the University of Chicago, on December 28, 1996. They are professors in the same department.^[7]