Ichijinsha (Japanese: 株式会社一迅社, Hepburn: Kabushiki-gaisha Ichijinsha) is a Japanese publishing company focused on manga-related publication, including magazines and books.

The company was first established in August 1992 as a limited company under the name Studio DNA whose main purpose was to edit shōnen manga.

In December 2001, a publishing company was formed named Issaisha which started the shōjo manga magazine Monthly Comic Zero Sum.

In March 2005, Studio DNA and Issaisha merged into the current Ichijinsha company.

[1] In October 2016, Ichijinsha was acquired by Kodansha and became its wholly owned subsidiary.