Mary Jane West-Eberhard (born 1941) is an American theoretical biologist noted for arguing that phenotypic and developmental plasticity played a key role in shaping animal evolution and speciation. She is also an entomologist notable for her work on the behavior and evolution of social wasps. She is engaged in long-term research projects at the Smithsonian Tropical Research Institute at the Escuela de Biologia, Universidad de Costa Rica.