Kumiko Saiki is a Japanese manga artist and illustrator who began her professional career in 1995. She was born on October 28, though the year of her birth is not publicly documented. Saiki has primarily worked within the shōjo manga genre, creating stories with varied themes and an artistic style noted for its clean lines. Over the course of her career, she has been credited with more than fifteen different manga series.

Saiki is best known as the creator of Kageki Shoujo!!, a manga series about students at a rigorous all-girls music school who aspire to join a theatrical troupe. The story is strongly inspired by the Takarazuka Revue, a famous all-female theater company in Japan. The series originated as Kageki Shoujo! (with a single exclamation mark), which was serialized in Shueisha's seinen magazine Jump Kai from 2012 to 2014 and later compiled into two tankōbon volumes. The publication of the series was halted when Jump Kai ceased its run in October 2014.

The manga was relaunched under Hakusensha as a single omnibus volume titled Kageki Shoujo!! Season Zero in March 2019. A sequel series, now titled Kageki Shoujo!! (with two exclamation marks), began serialization in Hakusensha's shōjo magazine Melody in 2015 and has continued to the present, with multiple tankōbon volumes released. The sequel and its prequel have been licensed for English publication in North America by Seven Seas Entertainment.

In October 2020, it was announced that Kageki Shoujo!! would receive a television anime adaptation, which later premiered in July 2021. The anime was produced by the studio Pine Jam and directed by Kazuhiro Yoneda. In an interview, Saiki explained that her editor first suggested she create a manga about performance arts. She chose the setting of an all-girls music school because of her personal fondness for stories exploring sisterhood and the bonds between women.

Recurring themes in Saiki's work include the harsh realities behind a glamorous profession, personal trauma, and the resilience of young women. The narrative of Kageki Shoujo!! deals with difficult subjects such as eating disorders, stalking, and childhood sexual abuse, which the creator has said she prefers to depict unflinchingly while also showing supportive adult figures who can guide the teenage characters. Saiki has stated that the influential manga The Rose of Versailles was the first comic ever bought for her, and it inspired her both to draw repeatedly and to ultimately pursue a career as a manga artist. The series Kageki Shoujo!! itself was nominated for the Kodansha Manga Award in the shōjo category in 2020, marking a significant recognition of her work within the industry.