Gregory Benford is an American science fiction author and astrophysicist who is on the faculty of the Department of Physics and Astronomy at the University of California, Irvine. He is also a contributing editor of Reason magazine.

As a science fiction author, Benford is perhaps best known for the Galactic Center Saga novels, beginning with In the Ocean of Night (1977). This series postulates a galaxy in which sentient organic life is in constant warfare with sentient electromechanical life.

Benford was born in Mobile, Alabama. He received a Bachelor of Science in physics in 1963 from University of Oklahoma in Norman, Oklahoma, followed by a Master of Science from the University of California, San Diego in 1965, and a doctorate there in 1967. That same year he married Joan Abbe. Benford modeled characters in several of his novels after her, most prominently the heroine of Artifact. She died in 2002.

Benford has an identical twin brother, Jim Benford, with whom he has collaborated on science fiction stories. Both got their start in science fiction fandom, with Gregory co-editor of the science fiction fanzine Void. Benford has said he is an atheist, though his views are not settled.

He has been nominated for four Hugo Awards (for two short stories and two novellas) and 12 Nebula Awards (in all categories). In addition to Timescape, he won the Nebula for the novelette “If the Stars Are Gods” (with Eklund).