Thrice is an American post-hardcore/experimental rock band that formed in Irvine, California in 1998. The lineup consists of Dustin Kensrue (vocals and guitar), Teppei Teranishi (guitar), Eddie Breckenridge (bass), and Riley Breckenridge (drums).

In 2000, Thrice signed with Sub City Records and released two LP's. The first, Identity Crisis (2000), only received 1.5 stars in the AMG review and little buzz. The second, The Illusion of Safety (2002), was widely acclaimed and received attention from major record labels. Even though Thrice's music has always included some metal influences, The Illusion of Safety contained a heavier metalcore sound. The album was recorded in Beltsville, Maryland and the track The Beltsville Crucible reflects this.

In 2003 Thrice signed up with Island Records and released The Artist in the Ambulance, which featured more structured songs while keeping true to their hardcore influences. In 2005 a DVD outlining their entire career to date was released under the title If We Could Only See Us Now. It included a CD with live tracks from the Apple Store and various b-sides.

Thrice released their fourth full-length album, Vheissu, on October 18, 2005. The album was characterized by many critics as being experimentally different, using non-traditional Thrice elements in the process. From keyboard melodies ("For Miles") to Japanese music-box undertones ("Music Box") to chain gang chant choruses ("The Earth Will Shake"), Vheissu introduced a new sound to the band's post-hardcore roots. UK producer Steve Osborne, whose past credits include many Brit-pop hits, was sought by Thrice to gain a new perspective on the songwriting process, enabling the band to expand their musical influences and produce a different album. The album garnered widespread critical acclaim and peaked at #15 on the Billboard 200.

The band released Red Sky, an EP comprised of various b-sides as well as live recordings, shortly after Vheissu.

Thrice released the first and second volume of The Alchemy Index, a highly experimental project based on the four traditional elements (fire, water, earth, and air), on October 16th 2007. Over the summer Thrice parted ways with Island records and signed with Vagrant. The Alchemy Index Vols. I & II - Fire & Water was released on October 16, 2007, and sold 28,000 copies in its first week. The album consists of the first two volumes, Fire and Water, and features 12 songs, 6 on each disk. The third and fourth volumes, Air & Earth were released on April 15, 2008.

The "Fire" disc features the heavier post-hardcore sound traditional Thrice fans will quickly embrace, harking back to their pre-Vheissu albums. The "Water" disc, however, is comprised of ambient songs similar to those found in Vheissu, Thrice's previous album release. The "Air" disc brings a whole new element of electronic elements and delayed guitar riffs to Thrice's sound. In "Earth", much like Dustin Kensrue's solo album, "Please Come Home", Thrice introduces an indie-folk sound combining intricate piano and acoustic guitar.

To promote the new album, Thrice toured with the bands mewithoutYou and Brand New. In promotion of Air & Earth, Thrice toured with Circa Survive and Pelican.