Ishikawa Chiyomatsu (石川 千代松, January 30, 1861 – January 17, 1935) was a Japanese biologist, zoologist, evolutionary theorist, and ichthyologist at the Naples Zoological Station starting 1887. He was responsible for disseminating Darwin's ideas on evolution in Japan. After graduating from the University of Tokyo, he studied in Germany under eminent evolutionary theorist August Weismann.