Diffuser is a pop punk band from the Long Island area that formed in 1994. As of 2005, they have released two albums, Injury Loves Melody (2001) and Making the Grade (2003), both with Hollywood Records. Their single Karma was included on the soundtrack for Mission: Impossible 2, and peaked at number 20 on the Billboard Mainstream Rock Tracks chart.

The band's members were formerly known as "Flu Thirteen", under which name they released the album In the Foul Key of V in 1998.