Symphony X is an American progressive/power metal band from New Jersey founded in 1994 by guitarist Michael Romeo.

Their 1997 album The Divine Wings of Tragedy and their 2000 release V: The New Mythology Suite have gained the band considerable attention within the progressive metal community. Musically Symphony X is similar to, although heavier than most other progressive metal bands to which they are commonly compared: Dream Theater, Fates Warning and Pain of Salvation. They play in a very syncopated, progressive fashion, also incorporating elements of symphonic metal into their sound. Their music contains strong neoclassical elements in line with the music of Yngwie Malmsteen, Randy Rhoads and other influential neoclassical metal artists.