Underground Sound of Lisbon (sometimes shortened to USL) is a collaboration between Portuguese house music producers Rui da Silva (then known as Doctor J) and DJ Vibe (real name Tó Pereira), who were active between 1993 and 2001. In 2014, USL returned to the stage to perform at the Rock in Rio Lisboa Electronic Stage.

The duo started working together in 1993 by founding Kaos Records, the first Portuguese electronic music label, with promoter António Cunha. They released their first record as Underground Sound of Lisbon, Chapter One, in 1994, although at that time they also signed their production work as LHT (Lisbon Hard Team).

But the USL moniker prevailed, becoming much more internationally recognized after the track "So Get Up", a hard tribal anthem with spoken-word apocalyptic proclamations by Californian vocalist-lyricist Ithaka Darin Pappas (more often known simply as Ithaka, but credited on that specific release as "Korvowrong"), received airplay in New York clubs at the hands of DJ Junior Vasquez, which led to a worldwide release at the Tribal America label. They also produced a track with house diva Celeda on the vocals called "Are You Looking For Me".

In 1998, USL contributed "Hailwa Yenge Oike Mbela" to the AIDS benefit compilation album Onda Sonora: Red Hot + Lisbon produced by the Red Hot Organization.

By the late 1990s their tribal house sound morphed into a more progressive and dreamy vibe. After the release of their final album, Etnocity, the duo officially entered an indefinite hiatus, as both artists wanted to branch out into other fields and work with other producers. Da Silva relocated to London, where he set up Kismet Records and started touring the world, while Vibe continued to tour worldwide and began working with up-and-coming Portuguese producers.