Okamoto Ippei (岡本一平) (June 11, 1886 – October 11, 1948) was a Japanese illustrator, cartoonist, and writer.

He studied Western-style painting at Tokyo School of the Arts under the instruction of Japanese painter Fujishima Takeji.

[2] Okamoto traveled to Europe and the United States and brought to Japan several comics.

He opened a school called Ippei Juku, where he was teacher of cartoonists Hidezo Kondo and Yukio Matsuura.

[3] Manga artist Osamu Tezuka mentioned Okamoto as one of his main influences.