The Unholy Alliance Tour is a biennial heavy metal concert tour of Europe and North America, with the tag-line "Preaching to the Perverted". The tour is headlined by the thrash metal band Slayer, and featured Trivium, Amon Amarth and Mastodon in its latest edition.

Europe 2004

The 2004 European edition of the tour featured the following bands: Slayer, Slipknot, Mastodon and Hatebreed. Typical Slayer Setlist "Darkness Of Christ [Audio Introduction] Encore: Typical Slipknot Setlist "Prelude 3.0" [Audio Introduction] "(515)" [played from tape] Danger - Keep Away [played from tape] Typical Mastodon Setlist

North America 2006

The 2006 North American edition of the tour, called "Chapter I", featured the following bands: Slayer as headliners, Lamb of God as "direct support" band, Children of Bodom and Mastodon in rotating slots, Thine Eyes Bleed as opening act. The Vancouver show was filmed for a forthcoming DVD, with camera angles from above the bands and in among the audience. The DVD was released on October 30, 2007.

Europe 2006

2006 European edition, called "Chapter II", featured the following bands: Slayer as headliners, In Flames as "direct support" band, Children of Bodom and Lamb of God in rotating slots, Thine Eyes Bleed as opening act. The lineup was identical to the American leg except for Mastodon, who were replaced by In Flames. The French group Gojira was the second band to perform in Paris on November 7, 2006.