Eörs Szathmáry (born 1959) is a Hungarian theoretical evolutionary biologist at the now-defunct Collegium Budapest Institute for Advanced Study and at the Department of Plant Taxonomy and Ecology of Eötvös Loránd University, Budapest. He is the co-author with John Maynard Smith of The Major Transitions in Evolution, a seminal work which continues to contribute to ongoing issues in evolutionary biology. He is a member of the Batthyány Society of Professors.