Sara Cosette Billey (born February 6, 1968, Alva, Oklahoma, USA) is an American mathematician working in algebraic combinatorics. She is knownfor her contributions on Schubert polynomials, singular loci ofSchubert varieties, Kostant polynomials, Kazhdan–Lusztig polynomials often using computer verified proofs. She is currently a member of the faculty at the University of Washington. In 2012 she became a fellow of the American Mathematical Society.