Iwasaki Yatarō (岩崎 弥太郎, January 9, 1835 – February 7, 1885) was a Japanese industrialist and financier known as the founder of Mitsubishi, one of Japan's largest conglomerates.

Iwasaki left for Edo aged nineteen for his education, but his studies were interrupted a year later when his father was seriously injured in a dispute with the village headman.

Iwasaki returned to Edo, where he socialised with political activists and studied under the Yoshida Toyo, a reformist and modernization advocate from Tosa Province.

Yoshida was employed by Yamauchi Toyoshige, the daimyō (lord) of the Tosa Domain, and he influenced Iwasaki with ideas of opening and developing the then-closed Japan through industry and foreign trade.

In 1873, the company changed its name to Mitsubishi, a compound of mitsu ("three") and hishi (literally, "water chestnut", often used in Japanese to denote a rhombus or diamond).

In 1903, Iwasaki's fourth daughter, Masako, married Baron Shidehara Kijūrō, the first Prime Minister of Japan after World War II.