Sakutarō Iwasa (岩佐 作太郎, Iwasa Sakutarō, 1879–1967) was a Japanese anarchist who was involved in the Japanese anarchist movement during the 20th century. Living until the age of 87, he was significant in influencing Japanese anarchists towards his anarcho-communist variety of 'pure' anarchism. It was said about him after his death that "the road which the aged Iwasa walked, extending through the Meiji, Taishō and pre-war and post-war Shōwa eras, was the history of the Japanese anarchist movement itself."