Baron Hisaya Iwasaki was a 19th- and 20th-century Japanese industrialist who served as the third head of the unified Mitsubishi.

The eldest son of the founder Yataro and his wife Kise, he was born in an area now called Aki, Kochi, on 14 October 1865.

He matriculated at the University of Pennsylvania in 1886 and, after earning his Bachelor of Science degree, returned to Japan in 1891.

His notable achievements as head of Mitsubishi include the modernisation of the Nagasaki shipyard and the development of Marunouchi as a modern business district.

[4] He married Shizuko, the daughter of Viscount Masaari Hoshina, 10th head of the Iino domain.