was a Japanese seinen manga magazine published by Futabasha.
Monthly Action was launched on May 25, 2013, the anniversary of publisher Futabasha's founding. The magazine was formed from a merging of the editorial departments of the manga magazines Manga Action, Comic High!, and '. While typically categorized as seinen magazine (manga for young adult men), the magazine follows a philosophy of publishing "anything interesting", and does not strictly conform to a specific genre or target demographic. The magazine launched with ', a series based on a fictional in-universe super hero from the manga series Crayon Shin-chan.
The magazine ended its publication on February 24, 2024, with its current series transferred to other magazines. Miss Kobayashi's Dragon Maid, Tsugumomo, ', Wazato Miseteru? Kamoi-san, and Kawasemi-san no Tsuri Gohan moved to sister magazine Manga Action. Other series, including the four Miss Kobayashi's Dragon Maid spinoff manga, were all transferred to the Web Action manga website.àHina no Mama ja Dame Desu ka? and Seiten no Ordo - Talc Teikoku Kà Âkyë Hishi manga both published their final chapters in the issue.