"Illumination Theory" is a song by American progressive metal band Dream Theater.

The song was released on 23 September 2013, as the closing track of the band's 12th album Dream Theater.

[1] The song's lyrics, according to the guitarist John Petrucci, are about things for which people will live, die or kill.

[2] The song's length is 22:17, making it Dream Theater's fifth longest to date.

The entire song was released as a 12" picture disc exclusively for Record Store Day 2014 and limited to 2,700 copies.