Sukeban Deka (スケバン刑事（デカ）, lit. 'Delinquent Girl Detective') is a Japanese manga series written and illustrated by Shinji Wada. It was serialized in Hana to Yume from 1975 to 1982 and collected into 22 volumes. Sukeban Deka has been adapted into three live-action television series, an original video animation (OVA) series, and three feature films, the last of which was released as Yo-Yo Girl Cop in 2006. It has also inspired four spin-off manga: Sukeban Deka If (スケバン刑事ｉｆ), a short story collection published in 2004, and Toki o Kakeru Sukeban Deka (時をかけるスケバン刑事), Re: Sukeban Deka (Re:スケバン刑事), and Sukeban Deka Pretend (スケバン刑事 Pretend), three ongoing series that premiered in Monthly Princess in 2021.

A 16-year-old sukeban (delinquent schoolgirl) named Saki Asamiya is offered by the police to become an undercover detective to escape prison. She initially refuses, so the police blackmail her by offering to pardon her mother, who is on death row for killing her husband, eventually forcing her to accept. Put under the tutelage of officer Kyouichiro Jin, she is given a metal yo-yo that doubles as a weapon as well as a police badge, and is made to infiltrate high schools around Japan to investigate and stop criminal activities. Her first destination is her former school, Takanoha High School, where Saki's place has been taken by the three Mizuchi sisters and their ring of illegal activities.

The creation of Sukeban Deka was the result of a misunderstanding between the author Shinji Wada and the editors at Hakusensha. Wada was developing a high school drama, but the publisher expected a detective story starring a high school student. At an impasse, Wada decided to combine the two concepts. Wada first published a pilot chapter titled "Kōsha wa Moete Iruka?" (校舎は燃えているか？, lit. "Is the School Building Burning?") in the August 5, 1975 (No. 15) issue of Hana to Yume magazine. Later, Sukeban Deka became a serial, starting in the January 5, 1976 (No. 1) issue of the same magazine, released in 1975. Disappointed that he could never end a complete serial before, Wada planned earlier in production a dramatic final scene in which the protagonist would die. The last chapter of this original planning was serialized in the December 20, 1977 (No. 24) issue, and was followed by an epilogue in the January 20, 1978 (No. 2) issue.

Following Sukeban Deka's conclusion, Wada started a new serial, Pygmalio [ja], in the March 20, 1978 (No. 6) issue of Hana to Yume. However, after one year of serialization, the series was poorly received by readers, and Wada stopped it to restart Sukeban Deka. Wada dubbed it as "part 2", and Sukeban Deka resumed in the February 5, 1979 (No. 3) issue, announced as a "new series". The manga ran regularly in Hana to Yume until its December 5, 1982 (No. 24) issue.

Since the original serialization, Sukeban Deka has been printed in four different collected editions; the original twenty-two volume tankōbon publication started on April 20, 1976, and ended on April 25, 1983. Hakusensha released a six-volume aizōban edition between March 3, 1987, and April 29, 1987, and a twelve-volume bunkoban edition between March 23, 1995, and June 21, 1995. The last reprint was done by Media Factory, who published twelve collected volumes between August 23, 2004, and July 23, 2005.

During their panel at Otakon 2026, KiraKira Media announced that they had licensed the series for English publication and will add it to their Omoi app.

Wada published two Sukeban Deka short stories set in a parallel universe in the October 1998 and May 1999 issues of Hakusensha's Melody magazine. He published two more installments in the March and April 2003 issues of Media Factory's Monthly Comic Flapper magazine. Media Factory later collected the chapters in a tankōbon volume titled Sukeban Deka If (スケバン刑事ｉｆ), which they published under the MF Comics imprint on June 23, 2004.

In 2021, almost a decade after Wada's death, Akita Shoten launched three spin-off manga series in Monthly Princess magazine. The first, Toki o Kakeru Sukeban Deka (時をかけるスケバン刑事, lit. "The Delinquent Girl Detective Who Leapt Through Time"), is written and illustrated by Saori Muronaga. It was serialized from the February 2021 issue of Monthly Princess on January 6, 2021 to the July 2023 issue on June 6, 2023. The second, Re: Sukeban Deka (Re:スケバン刑事), is written and illustrated by Ashibi Fukui [ja]. It was serialized from the March 2021 issue of the magazine on February 5, 2021, to the August 2025 issue on July 4, 2025. The third, Sukeban Deka Pretend (スケバン刑事 Pretend), is written by Sai Ihara [ja] and illustrated by Shingi Hosokawa. It was serialized from the September 2021 issue of Monthly Princess on August 6, 2021, to the April 2024 issue on March 6, 2024.