Kaiju No. 8 (Japanese: 怪獣8号, Hepburn: Kaijū Hachigō), also known in English as Monster #8, is a Japanese manga series written and illustrated by Naoya Matsumoto. It has been serialized on Shueisha’s Shōnen Jump+ app and website since July 2020, with its chapters collected in 12 tankōbon volumes as of April 2024. Viz Media has licensed the series for English release in North America.