The manga is a spin-off of Kamachi's A Certain Magical Index light novel series, taking place before and during the events of the main story.

A spin-off manga series titled A Certain Scientific Railgun: Astral Buddy began serialization in Dengeki Daioh from April 2017 to July 2020.

The series focuses on the exploits of Mikoto and her friends Kuroko Shirai, Kazari Uiharu, and Ruiko Saten, prior to and during the events of A Certain Magical Index.

A Certain Scientific Railgun is illustrated by Motoi Fuyukawa and started serialization in the April 2007 issue of ASCII Media Works' Dengeki Daioh.

[2] A 24-episode anime television series adaptation that was produced by J.C. Staff and directed by Tatsuyuki Nagai aired in Japan between October 3, 2009 and March 20, 2010.

[3] The anime was collected into eight DVD and Blu-ray Disc sets released between January 29 and August 27, 2010, with each volume containing a short story series titled A Certain Magical Index: Kanzaki SS.

The song "Smile (You & Me)" by Elisa, which uses the same tune as "Dear My Friend (Mada Minu Mirai e)", is featured as the ending theme for episode twelve.

[25] A visual novel based on A Certain Scientific Railgun for the PSP was released on December 8, 2011 after facing several delays, and comes in a special edition which includes a Kuroko Shirai Figma figure.

It is written by Kamachi and illustrated by Kiyotaka Haimura, Fuyukawa, Chuya Kogino, Arata Yamaji, Yasuhito Nogi, Teto Tachitsu, and Nankyoku Kisaragi.

[30] In September 2020, the anime series garnered over 300 million views in China through the Chinese streaming platform Bilibili.