Accel World (Japanese: アクセル・ワールド, Hepburn: Akuseru Wārudo) is a Japanese light novel series written by Reki Kawahara and illustrated by HIMA [ja]. It has been published by ASCII Media Works under its Dengeki Bunko imprint since February 2009. The series has spawned three manga series; Accel World by Hiroyuki Aigamo [ja], published in Dengeki Bunko Magazine from April 2010 to June 2017; Acchel World by Ryuryū Akari [ja], published in the same magazine from April 2010 to June 2016; and Accel World / Dural: Magisa Garden by Ayato Sasakura, published in Monthly Comic Dengeki Daioh from January 2012 to June 2017. The light novel series and its manga adaptation of the same name have been licensed for English release in North America by Yen Press.

A 24-episode anime adaptation produced by Sunrise aired between April and September 2012. It was licensed by Viz Media and began streaming in English on its Neon Alley service in April 2013. Two video games were released for the PlayStation Portable and PlayStation 3 in September 2012 and January 2013, each containing an original video animation (OVA) episode. An anime film titled Accel World: Infinite Burst featuring an original story by Kawahara premiered in Japan in July 2016.

Haruyuki "Haru" Arita is a short, overweight boy who is frequently ridiculed by delinquents at the Umesato Junior High School. Using his Neuro Linker to escape the torment of real life, he logs onto the school's local network cyberspace where he always plays virtual squash alone, and his innate video game skills bring him to the attention of Kuroyukihime (literally meaning "Black Snow Princess"), the school's popular, highly intellectual and attractive female student council vice-president.

After helping him against the delinquents, Kuroyukihime introduces Haruyuki to Brain Burst, a secret program that is able to accelerate the human cognitive process to the point at which time appears to stop. Haruyuki soon learns that Brain Burst is more than just a program, but an augmented-reality massively-multiplayer online (ARMMO) fighting game where people fight each other in fierce duels in order to obtain burst points, which can be spent for acceleration abilities in the real world.

Kuroyukihime then enlists Haruyuki's help in reaching level 10 within Brain Burst by defeating the "Six Kings of Pure Colour" and ultimately meeting the creator of Brain Burst to learn its true purpose. With every challenge they face in the accelerated world, Haru and Kuroyukihime, under their aliases "Silver Crow" and "Black Lotus", gather trusted allies and confront treacherous enemies. Their bond grows stronger while working to attain their ultimate objective: to reach the highest in-game level and meet the game's creator, who will reveal why the game was created and the true purpose of it.

Accel World began as a light novel series written by Reki Kawahara and illustrated by HIMA [ja]. Originally, Kawahara entered the first novel in the series into ASCII Media Works' 15th Dengeki Novel Prize in 2008 and the novel won the Grand Prize. The first novel was published by ASCII Media Works on February 10, 2009, under their Dengeki Bunko imprint. As of August 2025, 28 volumes have been published. At their Japan Expo USA panel, Yen Press announced the rights to publish the light novels in English. The English version is translated by Jocelyne Allen. The first volume was released on July 22, 2014.

A manga adaptation by Hiroyuki Aigamo [ja] was serialized in ASCII Media Works' Dengeki Bunko Magazine between April 10, 2010, and June 9, 2017. Its chapters were collected in eight tankōbon volumes, released between July 27, 2011, and July 27, 2017.

In North America, the manga has been licensed for English release by Yen Press. The English translation is by Jocelyne Allen. The volumes were released between September 23, 2014, and December 11, 2018.