The first season of the Japanese animated television series A Certain Scientific Railgun, based on the manga of the same name, follows the third Level 5 esper in Academy City named Mikoto Misaka. Produced by J.C.Staff, the season was directed by Tatsuyuki Nagai from a series composition supervised by Seishi Minakami.

A Certain Scientific Railgun is a Japanese manga series written by Kazuma Kamachi and illustrated by Motoi Fuyukawa, which began serialization in the April 2007 issue of ASCII Media Works' Dengeki Daioh magazine. 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. Seven Seas Entertainment began publishing the series in North America in June 2011. An anime television series adaptation by J.C.Staff aired in Japan between October 2009 and March 2010, followed by an original video animation released in October 2010. A second season titled A Certain Scientific Railgun S aired between April and September 2013. A spin-off manga series titled A Certain Scientific Railgun: Astral Buddy began serialization in Dengeki Daioh from April 2017 to July 2020. A third season titled A Certain Scientific Railgun T aired between January and September 2020.