Motoi Fuyukawa is a Japanese illustrator and manga artist, best known as the artist for the long-running manga series A Certain Scientific Railgun. He is not the author of the story but the illustrator, working from original concepts and plots provided by the series creator, Kazuma Kamachi. This role has made him a central visual contributor to the wider A Certain Magical Index franchise.

Before his professional debut, Fuyukawa was a member of the doujin circle House of KARSEA, where he drew fan works based on popular series such as Azumanga Daioh and Yotsubato!. His work caught the attention of editor Kentarou Ogino, which led to his selection as the artist for a new manga spin-off centered on the character Mikoto Misaka. He was one of several candidates for the position and was asked to produce character designs and sample scenes before being chosen, a decision that surprised him. Following his selection, he had the opportunity to meet with author Kazuma Kamachi and editor Kazuma Miki.

Fuyukawa's sole major manga credit, and the work for which he is most recognized, is A Certain Scientific Railgun. The series began serialization in ASCII Media Works' Dengeki Daioh magazine in February 2007 and continues to run. The story, which focuses on the everyday lives and dangerous adventures of Mikoto Misaka and her friends in Academy City, is a spin-off of the A Certain Magical Index light novel series. In this capacity, Fuyukawa has also provided front cover designs and illustrations for several short stories and side novels within the franchise, including Railgun SS: Liberal Arts City and its sequels. A collection of his artwork, titled Fuyukawa Motoi Illustrations, was published in 2013.

As the original manga creator, Fuyukawa receives credit for the source material upon which the anime adaptations are based. He is credited as the original creator, alongside Kazuma Kamachi, for the 2009 anime adaptation of A Certain Scientific Railgun, its second season Railgun S, and the third season Railgun T. His role in these productions is that of the manga artist, not a direct producer or writer for the anime itself.

In interviews, Fuyukawa has provided insight into his artistic process and challenges. He has noted that he initially tried to strictly follow the character designs of Kiyotaka Haimura, the illustrator of the original light novels, but eventually began drawing the characters in his own style. He has mentioned that his character designs tend to make the figures look taller compared to Haimura's or Chuya Kogino's interpretations. Fuyukawa has stated that his favorite character to draw is Mikoto Misaka, as he finds her expressions varied and fun to illustrate. Conversely, he has found the character Kuroko Shirai the most difficult to capture. He has also openly admitted to having trouble drawing technological elements, explosions, electricity, and other special effects, which were new challenges for him when he started working on the series. He has said he finds scenes where Mikoto fires her signature Railgun attack the most exciting to draw.

Fuyukawa's significance in the industry is tied directly to the success and longevity of A Certain Scientific Railgun. His visual storytelling has defined the look and feel of the science side of Academy City for a substantial portion of the franchise's existence. His work on the manga has directly spawned multiple successful anime seasons, an OVA, and video game adaptations, solidifying the Railgun series as a major property in its own right alongside the original Index story. His collaboration with Kazuma Kamachi, in which he receives plot frameworks and expands them into a full manga, has been a successful model for spin-off series.