Frances Hamilton Arnold (born 25 July 1956) is an internationally recognized American scientist and engineer. She pioneered methods of directed evolution to create useful biological systems, including enzymes, metabolic pathways, genetic regulatory circuits, and organisms. She is the Dick and Barbara Dickinson Professor of Chemical Engineering, Bioengineering, and Biochemistry at the California Institute of Technology, where she studies evolution and its applications in science, medicine, chemicals and energy. 

She earned her B.S. in Mechanical and Aerospace Engineering from Princeton University in 1979 and her Ph.D. in Chemical Engineering from the University of California, Berkeley. There, she did her postdoctoral work in biophysical chemistry before coming to Caltech in 1986.She won Charles Stark Draper Prize in 2011 for her individual contributions to directed evolution, a process which allows researchers to guide the creation of certain properties in proteins and cells. This technique has been used in food ingredients, pharmaceuticals, toxicology, agricultural products, gene delivery systems, laundry aids, and biofuels