Marc Davis (born 1947) is an American professor of astronomy and physics at the University of California, Berkeley.
In the 1980s, at Berkeley, he was part of a collaboration with George Efstathiou, Carlos Frenk and Simon White that established the validity of the "cold dark matter" theory for the formation of galaxies and other cosmic structures, now the accepted interpretation in cosmology.
In a classic series of papers, that collaboration — often called DEFW by their peers — used computer code to simulate the growth of the universe and resolve disputes among theoretical models.
He has also helped organize and run an all-sky model of cosmic dust distribution in the Milky Way galaxy.
While working on the DEEP survey, Davis suffered a stroke in June 2003 which has affected his right limbs although he continues to enjoy one of the main passions in his life, skiing.