Basilisk (Japanese: バジリスク〜甲賀忍法帖〜, Hepburn: Bajirisuku ~Kōga Ninpō Chō~, lit. Basilisk: The Kōga Ninja Scrolls) is a Japanese manga series written and illustrated by Masaki Segawa. Based on the 1958 novel The Kouga Ninja Scrolls by Futaro Yamada, it was serialized in Kodansha's Young Magazine Uppers from 2003 to 2004. The story takes place in the year 1614. Two ninja clans, Iga of Tsubagakure and the Kouga of Manjidani, battle each other to determine which grandson of Tokugawa Ieyasu will become the next shogun. The deadly competition between 10 elite ninja from each clan unleashes a centuries-old hatred that threatens to destroy all hope for peace between them.

A 24-episode anime television series by Gonzo was broadcast in Japan from April to September 2005. Segawa continued producing serialized adaptations of Futaro Yamada's novels with The Yagyu Ninja Scrolls in 2005, Yama Fu-Tang in 2010 and Jū: Ninpō Makai Tensei in 2012. Additionally, a two-part novel sequel titled The Ouka Ninja Scrolls: Basilisk New Chapter (桜花忍法帖～バジリスク新章, Ōka Ninpō Chō ~ Bajirisuku Shinfumi), penned by Masaki Yamada, was published in 2015 with illustrations by Segawa; a manga adaptation, Basilisk: The Ouka Ninja Scrolls (バジリスク〜桜花忍法帖〜, Bajirisuku Ōka Ninpō Chō~), illustrated by Tatsuya Shihira with character designs by Segawa, was serialized between 2017 and 2019, and an anime adaptation by Seven Arcs Pictures aired in 2018.

Basilisk won the 2004 Kodansha Manga Award for general manga.