Simon Asher Levin (born April 22, 1941) is an American ecologist. He is a Moffett Professor of Biology in the Department of Ecology and Evolution at Princeton University. He specializes in using mathematical modeling and empirical studies in the understanding of macroscopic patterns of ecosystems and biological diversities.He received Tyler Prize for Environmental Achievement in 2014 for his research revealing the complexity of, and relationships between, species and ecosystems. His work has been fundamental in the crafting of environmental policies and advancing the study of complex ecosystems – the myriad relationships and interactions in nature.