Hiroshi Saitō is a Japanese creator known primarily as a children's literature author, with his work serving as the original source material for anime and live-action adaptations. He is credited as the original creator behind the Obake Zukan franchise.

As a writer, Saitō has focused on works for young readers. The Obake Zukan picture book series, illustrated by Etsuyoshi Miyamoto, forms the basis of his most prominent anime-related credits. This series was first adapted into an anime television series titled Obake Zukan, which aired for 39 episodes from 2020 to 2021. A subsequent series, Obake Zukan!, followed with 13 episodes. For these anime productions, Saitō is credited as the original creator of the story, and he also wrote the lyrics for the opening theme song. The franchise expanded beyond animation with a live-action film adaptation titled Ghost Book Obakezukan, released in 2022, for which Saitō is credited with the original story.

Beyond his work on the Obake Zukan series, Saitō is the original creator of the children's novel Rudolf the Black Cat, which was adapted into an anime film in 2016. In that film, he also made a special appearance as a voice actor for the character Bicycle Uncle. His career as an author is distinct from that of other figures in the Japanese entertainment industry with the same name, including a veteran animator and director born in the 1930s known for his work on classic television anime, and a screenwriter born in 1959 who has written scripts for numerous live-action films.