Constance Elaine Trimmer Willis is an American science fiction writer.
She has won, among other awards, ten Hugo Awards and seven Nebula Awards. Willis most recently won a Hugo Award for All Seated on the Ground (August 2008). Willis is a 1967 graduate of Colorado State College, now the University of Northern Colorado.
She lives in Greeley, Colorado with her husband Courtney Willis, a professor of physics at the University of Northern Colorado. She also has one daughter, Cordelia.