Sailor Moon (Japanese: 美少女戦士セーラームーン, Hepburn: Bishōjo Senshi Sērā Mūn; originally translated as Pretty Soldier Sailor Moon, later Pretty Guardian Sailor Moon) is a Japanese manga series written and illustrated by Naoko Takeuchi. It was serialized in Kodansha's Nakayoshi magazine from 1991 to 1997. The series consists of 60 original chapters, later reorganized into 52 chapters, along with several side stories, and was collected into 18 tankōbon volumes.

Set in 1990s Tokyo, the story follows a schoolgirl named Usagi Tsukino, who transforms into Sailor Moon in search of the magical "Legendary Silver Crystal" (「幻の銀水晶」, Maboroshi no Ginsuishō, literally "Phantom Silver Crystal"). Alongside a team of fellow Sailor Soldiers—later referred to as Sailor Guardians—she battles powerful enemies to protect the Silver Crystal and prevent the destruction of the Solar System.

The manga was developed alongside an anime adaptation produced by Toei Animation, which aired in Japan from 1992 to 1997. The franchise later expanded with three animated feature films, a television special, and three short films. A live-action television adaptation, Pretty Guardian Sailor Moon, aired from 2003 to 2004, while a new anime adaptation, Sailor Moon Crystal, began streaming worldwide in 2014.

Outside Japan, the manga has been officially published in English by Kodansha Comics in North America and by Random House Australia in Australia and New Zealand. The anime has also been licensed for English-language release by Viz Media in North America and by Madman Entertainment in Australia and New Zealand.

Since its debut, Sailor Moon has received widespread critical acclaim for its artwork, memorable characters, and humor. The manga has sold more than 46 million copies worldwide, making it one of the best-selling manga series and one of the most successful shōjo manga titles in history. The anime adaptation also played a significant role in introducing Japanese animation to Western audiences, especially in the United States. As a multimedia franchise, Sailor Moon has generated more than US$2.5 billion in global merchandise sales.

The series focuses on Usagi Tsukino, a young middle school student in the Azabu-Jūban district of Tokyo in the 1990s, who learns from the talking cat Luna that she is actually a reincarnation of a princess from the Moon Kingdom, Sailor Moon. She is joined by Ami Mizuno, a student who awakens as Sailor Mercury; Rei Hino, a local Shinto shrine maiden who awakens as Sailor Mars; Makoto Kino, a tall and strong transfer student who awakens as Sailor Jupiter; and Minako Aino, a young aspiring idol who had awakened as Sailor Venus a few months earlier, accompanied by her talking feline companion Artemis. As they set out on their adventures, others join the Guardians later in the series, including Mamoru Chiba, a high school student who occasionally assists them as Tuxedo Mask; Chibiusa, Usagi and Mamoru's future daughter who awakens as Sailor Chibi Moon; Haruka Tenoh, a car-racer who can transform into Sailor Uranus; Michiru Kaioh, a violinist who can transform into Sailor Neptune; Setsuna Meioh, a physics student who can transform into Sailor Pluto; Hotaru Tomoe, who awakens as Sailor Saturn; and the Three Lights, pop idols who are really the Sailor Starlights. Together, they encounter extraterrestrials, space travelers, and other Guardians as they protect the Earth and the Moon from destruction by malevolent forces.