Liquid Tension Experiment is an instrumental progressive rock / metal project consisting of Dream Theater members John Petrucci (guitar), Jordan Rudess (keyboard), and Mike Portnoy (drums), as well as progressive rock icon Tony Levin (bass, Chapman stick) of King Crimson. Active between 1997-1999 - Regrouped in 2007 (as a trio) and again in 2008 (full band).

Liquid Tension Experiment had its genesis still in the year of 1996, when Dream Theater drummer Mike Portnoy was contected by Peter Morticelli (head of the label Magna Carta) and Mike Varney (vice president of the label Magna Carta) and was asked to, according to Portnoy, try and "put together a couple of Super Groups (for the lack of a better term!)". In spite of declining the offer at first, he eventually agreed to assemble a super ensemble. Many were the attempts to put the group together through most of 1997, but most of them failed due to one pivotal problem: they were lacking a member. Mike was able to recruit a bass player, who was Tony Levin, of King Crimson and Peter Gabriel's band fame, and a keyboard player, who was Jordan Rudess, which was playing with the jazz fusion group Dixie Dregs at the time, but there was still a guitarist missing. Every guitarist that was originally invited to be part of the group refused the offer due to conflicting schedules. Finally, in the spring of 1997, Mike decided to invite John Petrucci, Dream Theater guitarist, to join Liquid Tension Experiment and, with his acceptance, the group was finally complete and ready to record their first album, the self titled Liquid Tension Experiment. The idea, or the concept, of that album was to fully write, rehearse and record the whole thing in a week, and so it was done: from September 20 to September 25 of 1997 the whole process was successfully done and the album was released in the next year, in March of 1998. The members of the band and Magna Carta were so satisfied with the results of the first endeavor that they decided to record yet another album. In late 1998 the band regrouped and in the span of two months wrote, rehearsed and recorded what would be their second album, entitled Liquid Tension Experiment 2. This time, just like with Liquid Tension's first album, it was released on the following year. Nearly ten years after the disbandment of the Liquid Tension Experiment, in late 2007, a third studio album was released with new band material. The release entitled Liquid Trio Experiment had jam tracks from the band without John Petrucci, who was with his wife at the hospital expecting his child to be born at the time. Unlike the two previous studio albums, Liquid Trio Experiment was mostly ill received by critics and fans alike. On the tenth anniversary of the release of their self titled album, Liquid Tension Experiment decided to make a commemoration tour throughout the USA in 2008. Unfortunately, the tour did not went through other countries, but it spammed a considerable sum of live recordings that were released in the following year by Mike Portnoy's own recording label, the Ytsejam Records/Lazy Tomato. Liquid Tension Experiment's music could be described as the meeting of jazz fusion, heavy metal, latin music, funk, progressive rock and enormous doses of improvisation delivered by some of the best musicians the worlds of progressive rock, progressive metal and jazz have to offer.