Yasuda Zenjirō (安田 善次郎, November 25, 1838 – September 28, 1921) was a Japanese entrepreneur from Toyama, Etchu Province (present-day Toyama Prefecture) who founded the Yasuda zaibatsu (安田財閥). He donated the Yasuda Auditorium (安田講堂, Yasuda Kōdō) to the University of Tokyo. He was a maternal great-grandfather of Yoko Ono via his adoptive son, Yasuda Zenzaburō (安田善三郎).