Birgit Speh (born 1949) is a Distinguished 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 given tenure by Cornell University, and the first to receive the title of Professor.
In 2012, Speh became a fellow of the American Mathematical Society. She was selected to give the 2020 AWM-AMS Emmy Noether Lecture at the 2020 Joint Mathematics Meetings.