George David Tilman, is an American ecologist. He is Regents Professor and McKnight Presidential Chair in Ecology at the University of Minnesota and Distinguished Professor at the University of California, Santa Barbara's Bren School of Environmental Science & Management. He was elected to the U.S. National Academy of Sciences in 2002, and to the U. K. Royal Society as a Foreign Member in 2017 and awarded the U. S. National Medal of Science in 2025.