MUSTACH was formed in 1998 in Gothenburg as a Stoner / Hard Rock band by vocalist & guitarist Ralph Gyllenhammar (a.k.a. Ralph Lennart), guitarist Hannes Hansson, bassist Mats "Stam" Johansson and drummer Mats "Dojan" Hansson. Although officially being formed in 1998, the band members were not completely new to the scene and the history of MUSTASCH can be traced back to the early 90's. Even earlier, a very young Hannes Hansson once played in a punk band called SURE TRÅKINGS TRIO. The very same members of MUSTASCH had another Rock'n'Roll band called GRINDSTONE back in the early 90's. This act would then split up in 1995. For a while they considered restarting the band under a new name and play Hard Rock instead. One day on the way home from practice they were joking around about what to call the band and someone said as a joke MUSTASCH. After a while they considered the name to be pretty heavy and "manly", and, most likely, nobody would likely forget such a name.

This failed to transpire when in 1996 Ralf Lennart (as he was then called) replaced Tony Jelencovich in B-THONG, who went on to form TRANSPORT LEAGUE. Meanwhile Ralf's old band members were inactive while B-THONG released the album 'From Strength To Strength' in 1997. By 1998 the demise of B-THONG was looming near. Around this time Ralf and Hannes were sharing an apartment and jamming once again when they decided to start up their old band again. After contacting their old rhythm section of "Stam" and "Dojan", MUSTASCH was finally born and recorded a demo in late 1998 on the Mustasch Farm, an old estate located on the island Orust in Sweden.

These demo tracks would soon surface on several compilations. In 1999 the tracks 'Muddy Waters' on the 7" 'Daredevil Magazine - Burn the Streets Vol.1' and 'Homophobic/Alcoholic' on the 'Molten Universe - Volume One' set. Then in 2000 the tracks 'Coomber' on the album 'Underdogma - Judge Not...' and 'Taunus' on the CD 'Daredevil Magazine - Burned Down To Zero'.

By this time, MUSTASCH was gaining a following by touring and printing their own t-shirts. The members in MUSTASCH had been childhood friends with the members of SOUNDTRACK OF OUR LIVES living in Gothenburg, whom all supported MUSTASCH by wearing their t-shirts. Finally the hype reached Fredrik Wennerlund from EMI, living in Karlstad who asked the members of SOUNDTRACK OF OUR LIVES living there, who are these MUSTASCH guys? He was told "good Hard Rock from Gothenburg" and after checking them out he signed MUSTASCH in 2000 to Majesty, a sub-label of EMI. Also noteworthy from this year is that MUSTASCH appeared in a car commercial for Toyota Avansis, as a Rock band that wanted peace and quiet after their gig, when driving home in their silent car.

In February 2001 the EP 'The True Sound Of The New West' was released and along with increased touring helped establish MUSTASCH into the metal scene. Rave reviews followed and people began to describe the band's sound as a mixture of BLACK SABBATH meets THE CULT due to the heavy riff based songs, along with Ralf's powerful voice which was a dead ringer for Ian Astbury's voice.

Just as their previous EP, Roberto Laghi was once again was the choice producer for their dubut album 'Above All', released in March 2002. With this album MUSTASCH had the big hit 'Down In Black'. Their first full length album lasted 17 weeks on the Swedish top 40, and touring took the band across the border to Finland, Norway, Denmark, but most of all Germany, where they had a long and successful tour with GLUECIFER and ROSE TATTOO. Their appearance at the Roskilde festival was voted "The Best Concert 2002" and to top it off, MUSTASCH was nominated for Best Heavy Metal Album 2002 at the Swedish Grammy Awards. This same year, the book 'Swedish Hard Rock & Heavy Metal Volume 2' was released and featured the MUSTASCH demo song 'Log' on it's bonus CD compilation.

By 2003 the band decided to take it to the next level, attaining the services of producer Jacob Hellner, of RAMMSTEIN fame. The result 'Ratsafari' was released in September 2003, with the singles 'Black City' and '6:36', resulting in another Swedish Grammy-nomination for Best Heavy Metal Album 2003. Touring increased throughout Europe. Along with headline tours, they also supported MOTÖRHEAD on their German tour.

For the fourth recording the band decided to take things back to the basics, in order the catch their full live sound. They re-established a co-operation with their old friend and producer Roberto Laghi. In June 2005 'Ratsafari' was finally unleashed, preceded a month earlier by the single/video 'Dogwash' which gained major rotation on both TV and radio. November saw the release of yet another single/video in 'I'm Alright'. Once again, heavy touring commenced.

MUSTASCH signed to Bohus Entertainment to record a new album with producer Tobias Lindell in 2006. The 'Parasite' EP entered the Swedish charts at number 22 in May. The band contracted a new deal with Regain Records in September.

Former SPARZANA guitarist David Johannesson joined the band in October 2008.