Golgo 13 (Japanese: ゴルゴ13, Hepburn: Gorugo Sātīn) is a Japanese manga series written and illustrated by Takao Saito, published in Shogakukan's seinen manga magazine Big Comic since October 1968. The series follows the title character, a professional assassin for hire. Golgo 13 is the oldest manga still in publication, and its tankōbon edition was certified by Guinness World Records as the highest number of volumes for a manga series. Saito said before his death in 2021 that he wanted the manga to continue on without him and previously raised concerns the manga may be unfinished after he passes away. The Saito Production group of manga creators will continue its publication with the assistance of the Big Comic's editorial department.

The series has been adapted into two live-action feature films, an anime film, an original video animation, an anime television series and six video games.

With a cumulative total of 300 million copies in circulation in various formats, including compilation books, it is the second best-selling manga series and the top selling seinen manga series in history. The manga won the 1975 Shogakukan Manga Award for general manga and the Grand Prize at the 2002 Japan Cartoonists Association Awards.