Yu-Gi-Oh!, known in Japan as Yu-Gi-Oh! Duel Monsters (Japanese: 遊☆戯☆王デュエルモンスターズ, Hepburn: Yūgiō Dyueru Monsutāzu) and alternatively subtitled Rulers of the Duel in the United States and Canada, is a Japanese anime series animated by Studio Gallop based on the Yu-Gi-Oh! manga series written by Kazuki Takahashi. It is the second anime adaptation of the manga following the 1998 anime television series produced by Toei Animation. The series revolves around a young high school boy named Yugi Muto who battles opponents in the Duel Monsters card game. The series begins from chapter 60 in volume 7 before loosely adapting the remaining chapters of the original manga by making story changes that conflict with the events of the manga canon.

Yu-Gi-Oh! Duel Monsters originally aired in Japan on TV Tokyo from April 2000 to September 2004, running for 224 episodes; A remastered version, highlighting certain duels, began airing in Japan in February 2015. An English-language localization of the anime series was produced by 4Kids Entertainment, and aired in the United States from September 29, 2001, to June 10, 2006, on Kids' WB. Twelve extra episodes, which is American-produced, aired exclusively for the Western audience in mid-late 2006 shortly after the conclusion of the main series.

The series has since spawned its own metaseries. Duel Monsters would be succeeded by Yu-Gi-Oh! GX, Yu-Gi-Oh! 5D's, Yu-Gi-Oh! Zexal, Yu-Gi-Oh! Arc-V, Yu-Gi-Oh! VRAINS, Yu-Gi-Oh! Sevens, and Yu-Gi-Oh! Go Rush!!. Three films based on this anime series have also been produced: Pyramid of Light (2004), Bonds Beyond Time (2010) and The Dark Side of Dimensions (2016).