Act-Age (Japanese: アクタージュ, Hepburn: Akutāju) is a Japanese manga series written by Tatsuya Matsuki [ja] and illustrated by Shiro Usazaki [ja]. It was serialized in Shueisha's Weekly Shōnen Jump from January 2018 to August 2020, with its chapters collected into 12 tankōbon volumes. Act-Age was canceled and removed from the magazine and all official platforms after Matsuki's arrest in August 2020.

Viz Media published the first three chapters for its "Jump Start" initiative and then the series was simultaneously published from December 2018, after a restructuring of the English Shonen Jump. Shueisha also published the series in English on its Manga Plus platform from January 2019 to August 2020.

The story focuses on Kei Yonagi, a high school girl who strives to become an actress. She lives with her two younger siblings, after their father left them and their mother died. Kei has an extreme talent for method acting, to the point where she loses track of reality while acting. At an audition, some speculate that acting of this intensity could be self-destructive, and cite that as a reason for not accepting her. However, Kei catches the eye of the highly acclaimed director Sumiji Kuroyama, who steps forward with the intent of bringing out her full potential.

Written by Tatsuya Matsuki [ja] and illustrated by Shiro Usazaki [ja], Act-Age was serialized in Shueisha's shōnen manga magazine Weekly Shōnen Jump from January 22, 2018, to August 11, 2020. Shueisha collected the chapters into twelve individual tankōbon volumes, released from May 2, 2018, to July 3, 2020.

Viz Media published the first three chapters for its "Jump Start" initiative and then began to simultaneously publish the series in December 2018 after a restructuring of the English Shonen Jump. Shueisha also simultaneously published in English the series on the app and website Manga Plus starting in January 2019. In October 2019, Viz Media announced the print release of the manga; the first two volumes were released on July 7 and September 1, 2020, respectively.

On August 8, 2020, it was reported that Matsuki had been arrested for allegedly approaching and inappropriately touching two female middle school students in June 2020. Editors from Weekly Shōnen Jump stated that they would be taking the matter seriously, and later announced the series would immediately end publication with the chapter released on August 11. On August 17, 2020, Shueisha announced it had suspended all sales of the manga, and canceled the planned volume 13 and beyond. Viz Media and Manga Plus also decided to not publish the series' final chapter on their platforms. Viz Media removed its listing of further volumes.

Shiro Usazaki issued a statement on August 24, 2020, expressing sympathies for the victims and that they consider the cancellation to be appropriate, as they did not want the manga to be a work that triggers similar reactions from the victims. Despite regrets of having to end the manga mid-way, Usazaki urged fans of the series not to harass or blame the victims. On September 16, 2020, Matsuki was formally indicted for the second of the two indecent acts committed; Matsuki's sentencing was held on December 23 of that same year. The Tokyo District Court handed Matsuki a guilty verdict and a sentence of one year and six months in prison, suspended for three years (i.e., Matsuki would not serve his sentence if he remained on good behavior for three years).

These chapters were not published in a tankōbon volume. They were originally serialized in Japanese in issues of Weekly Shōnen Jump from April to August 2020.