Rurouni Kenshin: Meiji Swordsman Romantic Story (Japanese: るろうに剣心 -明治剣客浪漫譚-, Hepburn: Rurōni Kenshin -Meiji Kenkaku Roman Tan-) is a Japanese manga series written and illustrated by Nobuhiro Watsuki. The story begins in 1878, the 11th year of the Meiji era in Japan, and follows a former assassin of the Bakumatsu, known as Hitokiri Battosai. After his work against the bakufu, he becomes Himura Kenshin, a wandering swordsman who protects the people of Japan with a vow never to take another life. Watsuki wrote the series based on his desire to make a shōnen manga series different from others published at the time, with Kenshin being a former assassin and the story taking a more serious tone as it progressed.

Rurouni Kenshin was serialized in Shueisha's shōnen manga magazine Weekly Shōnen Jump from April 1994 to September 1999. Its chapters were collected in 28 tankōbon volumes; it was later republished in a 22-volume kanzenban edition and a 14-volume bunkoban edition. The manga was adapted into an anime television series, produced by SPE Visual Works and animated by Studio Gallop and later by Studio Deen, aired from January 1996 to September 1998. In addition to an animated feature film, Rurouni Kenshin: The Motion Picture, two series of original video animations (OVAs) were also produced; Rurouni Kenshin: Trust & Betrayal, which adapted stories from the manga that were not featured in the anime, and Rurouni Kenshin: Reflection, a sequel to the manga. In 2017, Watsuki began publishing a direct sequel, Rurouni Kenshin: The Hokkaido Arc, in Jump Square. A second anime television series adaptation by Liden Films premiered in July 2023. In addition, other media based on the franchise has been produced, including a series of five live-action theatrical film adaptations, beginning with Rurouni Kenshin in 2012 and ending with Rurouni Kenshin: The Beginning in 2021, and video games for the PlayStation, PlayStation 2, and PlayStation Portable. Several art and guidebooks have been published, and writer Kaoru Shizuka has written three official light novels, which were published by Shueisha.

The manga, as well as the first light novel and guidebook, have been published in North America by Viz Media. The Rurouni Kenshin manga had over 72 million copies in circulation by 2019, making it one of the best-selling manga series of all time. The series has received praise from various publications for manga, anime, and other media, particularly for the characters' designs and historical setting.

The series takes place in 1878, eleven years after the beginning of the Meiji era. After participating in the Boshin War as the assassin Hitokiri Battōsai, Himura Kenshin wanders the countryside of Japan, offering protection and aid to those in need as atonement for the murders he once committed. Having vowed to never kill again, he now wields a reverse-bladed katana. Upon arriving in Tokyo, he meets a young woman named Kamiya Kaoru, who is fighting a murderer who claims to be the Hitokiri Battōsai and is tarnishing the name of the swordsmanship school that she teaches. Kenshin decides to help her and defeats the fake Battōsai. After discovering that Kenshin is the true Hitokiri Battōsai, Kaoru offers him a place to stay at her dojo, noting that he is peace-loving and not cold-hearted, as his reputation had implied. Kenshin accepts and begins to form lifelong relationships with others, including Sagara Sanosuke, a former member of the Sekihō Army; Myōjin Yahiko, an orphan from a samurai family who also lives with Kaoru as her student; and doctor Takani Megumi, who has become involved in the opium trade. However, he also deals with old and new enemies, including the former leader of the Oniwabanshū, Shinomori Aoshi.

After several months living in the dojo, Kenshin faces Saitō Hajime, a rival from Bakumatsu who is now a police officer. This challenge turns out to be a test to face his successor, Shishio Makoto, who plans to conquer Japan by destroying the Meiji Government, starting with Kyoto. Feeling that Shishio's faction may attack his friends, Kenshin meets Shishio alone to defeat him. However, many of his friends, including a young Oniwabanshū named Makimachi Misao, whom he meets during his travels, decide to help him in his fight. After his first meeting with him, Kenshin realizes that he must become stronger to defeat Shishio without becoming the cold assassin he was in the past and returns to the man who taught him kenjutsu, Hiko Seijūrō, to learn the school's final technique. Finally accepting the help of his friends, he defeats Shishio, who dies after exceeding the limits of his abnormal body condition, after which a reformed Shinomori stays in Kyoto with the surviving Oniwabanshū.

When Kenshin and his friends return to Tokyo, he finds Yukishiro Enishi, who plans to take revenge. At this point, it is revealed that, during the Bakumatsu, Kenshin was to be married to Yukishiro Tomoe, who sought to avenge the death of her first fiancé, whom he had assassinated, but instead they fell in love and he proposed to her. Because she was related to the Edo guards who sought to kill Kenshin, they realized her deception and captured her to use as bait. In the final fight against the group's leader, Kenshin accidentally killed Tomoe after she took a blow meant for him. Seeking revenge for the death of his sister, Enishi kidnaps Kaoru and Kenshin and his friends set out to rescue her. A final battle between Kenshin and Enishi ensues, with Kenshin emerging victorious. Misao brings Tomoe's diary to Enishi, who keeps it in a village to hide along with his missing father.

Four years later, Kenshin has married Kaoru and has a son named Himura Kenji. Now at peace with himself, Kenshin gives his reverse-blade sword to Yahiko as a ceremonial gift.

A prototype series titled Rurouni: Meiji Swordsman Romantic Story appeared as two separate short stories published in 1992 and 1993. The first story, published in December 1992 in the Weekly Shōnen Jump Winter Special issue for 1993, featured an early version of Kenshin preventing a crime lord from taking over the Kamiya dojo. Watsuki described this first story, which echoed the later "Megumi Arc," as a pilot for Rurouni Kenshin. He stated that the final series was not entirely his own initiative; finding historical stories difficult, he had initially wanted to create a contemporary series. After an editor requested a new historical story, Watsuki developed a concept set in the Bakumatsu period inspired by Moeyo Ken (Burn, O Sword) with a narrative approach similar to Sanshiro Sugata. He experimented with various titles, including Nishin (Two-Hearts) Kenshin, Yorozuya (Jack-of-All-Trades) Kenshin, and variations of "Rurouni" and "Kenshin" using different kanji.