Jennifer Alice Clack, FRS, is an English paleontologist, an expert in the field of evolutionary biology. She studies the "fish to tetrapod" transition— the origin, evolutionary development and radiation of early tetrapods and their relatives among the lobe-finned fishes. She is best-known for her book Gaining Ground: The Origin and Early Evolution of Tetrapods, published in 2002 and written with the layman in mind. In 2006, Clack was awarded a personal chair by the University of Cambridge, taking the title Professor of Vertebrate Palaeontology.