Decemberunderground is the seventh studio album by American rock band AFI, released on June 6, 2006, through Interscope Records.

They were assisted by engineers Seth Waldmann, Jason Gossman, Kevin Mills, Eric Weaver, Dimitar Krnjaic and Keith Armstrong.

[8][9] Ed Thompson of IGN compared the album to bands such as U2, the Cure, the Smiths, Depeche Mode and Alphaville.

In late March 2006, the upcoming album was promoted by a cryptic contest known as "The Charlotte Mystery" that culminated in fans who solved the puzzles being invited to April 2006 private shows in Los Angeles, New York City, and San Francisco.

[16] Customers who pre-ordered the album at special pre-listening events received a CD of the "Miss Murder" single, which also contained a cover of INXS's song "Don't Change".

[22] Between June and August 2006, the band appeared at select stops on the 2006 Warped Tour and played various headlining shows, with support from the Dillinger Escape Plan and Nightmare of You.

[35][36] They closed out the year headlining the 91X Nightmare Before Xmas radio festival, and playing an AOL Session, where they performed "Endlessly, She Said".

[40][41][42] Preceded by one-off show in Mexico, AFI then went on a tour of Europe in April and May 2007, and appeared at Virgin Festival in Canada.

Havok and Puget then began to promote their side-project Blaqk Audio before beginning work on the eighth AFI album, Crash Love (2009).

[45] Entertainment Weekly awarded the album a grade of B+, and called it a further development of the band's earlier shift to "an eerie, metal-edged Cure sound", with Decemberunderground representing "the most melodically acute distillation of that style yet,"[47] unlike their previous studio album Sing the Sorrow, which they awarded a D. AllMusic awarded the album 4 out of 5 stars, saying the band's "ever-evolving goth-punk" sound is present on Decemberunderground in a "tighter and lighter" form, showing that the "core of AFI's sound never strays too far from what listeners have grown to love about them in the first place.

[54] The album was certified gold by the Recording Industry Association of America (RIAA) on August 30, 2006, and has sold at least 993,000 copies in the United States as of September 2009.