Decomposer is the second studio album by American pop punk band The Matches. It was released by Epitaph Records on September 11, 2006 worldwide, on September 12, 2006 in the United States, and in 2016 on vinyl. Audio production was handled by Matt Rad, Mike Green, Ryan Divine & Johnny Genius, Miles Hurwitz, Blink-182's Mark Hoppus, Goldfinger's John Feldmann, Rancid's Tim Armstrong, 311's Nick Hexum, and Bad Religion's Brett Gurewitz.

The Matches are an American rock band from Oakland, California, active from 1997 to 2009. Formed as the Locals, the group changed their name after five years to avoid conflict with a Chicago band of the same name. As the Matches, they self-released their debut album E. Von Dahl Killed the Locals in 2003, then signed to Epitaph Records who re-released it the following year. Decomposer followed in 2006, seeing the band move from their pop punk roots in a more idiosyncratic direction with contributions from nine different record producers; it reached no. 18 on Billboard's Independent Albums chart. With their third album, A Band in Hope (2008), their sound became even more heavily layered and experimental; it was their only release to chart on the Billboard 200, reaching no. 179.