**Birgit Speh** is a professor of mathematics at Cornell University. She is known for her work in Lie groups, including Speh representations (also known as Speh's representations).

Speh received her Ph.D. from Massachusetts Institute of Technology in 1977. She was the first female mathematician to be hired by Cornell University.

In 2012, Speh became a fellow of the American Mathematical Society.

Speh, Birgit; Vogan, David A., Jr. Reducibility of generalized principal series representations. *Acta Math.* 145 (1980)
Speh, Birgit. Unitary representations of Gl(*n*,**R**) with nontrivial (*g*,*K*)-cohomology. *Invent. Math.* 71 (1983), no. 3, 443–465.
Speh, Birgit. The unitary dual of Gl(3,**R**) and Gl(4,**R**). *Math. Ann.* 258 (1981/82), no. 2, 113–133.