Yaichirō Okada (岡田 彌一郎, Okada Yaichirō, June 24, 1892 – April 28, 1976) was a Japanese zoologist.[1] He was born in Ishikawa Prefecture.
Okada studied at the Imperial Fisheries Institute (now Tokyo University of Marine Science and Technology). He was a professor at Tokyo Higher Normal School (now University of Tsukuba), and after World War II he taught at Mie University from 1950, where he was dean of Fisheries.[2] After retirement he served as a professor at Tokai University.
As a zoologist, has contributed in the field of fish taxonomy, as well as reptiles and amphibians.[2] Okada's primary work in English was Fishes of Japan, which published in 1955 by Maruzen and subsequently issued in revised editions.[3]