The Kenkyusha Co., Ltd. (株式会社研究社, Kabushikigaisha Kenkyūsha) is a publishing house with headquarters in Chiyoda, Tokyo, Japan.
The predecessor of Senior High School English Study (高校英語研究, Kōkō Eigo Kenkyū) titled Examination and Student (受験と学生, Juken to Gakusei) was launched in 1917.
Kenkyūsha expands, establishing in 1919 a typesetting workshop on the slope of Kudan, a former street in Chiyoda, Tokyo, and — in 1920 — a printing house on Kagurazaka in Ushigome.
In 1944, Kenkyūsha receives an assignment from Aki Yasutarō for The Rising Generation (英語青年, Eigo Seinen), a monthly magazine aimed at researchers and students of English literature.
In 1963 the company publishes The Kenkyūsha Shakespeare (詳注シェクスピア双書, Shōchū Shekusupia Sōsho) consisting of 12 volumes.