Baron Kijūrō Shidehara(币原 喜重郎,Shidehara Kijūrō, 13 September 1872 – 10 March 1951) was a prominent pre–World War II Japanese diplomat and the 44th Prime Minister of Japan from 9 October 1945 to 22 May 1946. He was a leading proponent of pacifism in Japan before and after World War II, and was also the last Japanese prime minister who was a member of the kazoku. His wife, Masako, was the fourth daughter of Iwasaki Yatarō, founder of the Mitsubishi zaibatsu.