Hamaguchi Osachi (Kyujitai: ?? ??; Shinjitai: ?? ??, also Hamaguchi Yuko, 1 April 1870 – 26 August 1931) was a Japanese politician, cabinet minister and Prime Minister of Japan from 1929 to 1931.
Nicknamed the "Lion Prime Minister" (??????, Raion Saisho) due to his dignified demeanor and mane-like hair, Hamaguchi served as leading member of the liberal Rikken Minseito (Constitutional Democratic Party) during the "Taisho Democracy" of interwar Japan; he survived an assassination attempt by a right-wing fanatic in 1930, but died about eight months later.