Peter Douglas Ward (born 1949) is an American paleontologist and professor at the University of Washington, Seattle, and Sprigg Institute of Geobiology at the University of Adelaide. He has written numerous popular science works for a general audience and is also an adviser to the Microbes Mind Forum. In 2000, along with his co-author Donald E. Brownlee, he co-originated the term Rare Earth and developed the Medea hypothesis alleging that multicellular life is ultimately self-destructive.