Primus is an American rock band formed in 1984, currently composed of bassist/vocalist Les Claypool, guitarist Larry "Ler" LaLonde and drummer Jay Lane. Primus originally formed with Claypool and guitarist Todd Huth, later joined by Lane, though the latter two departed the band at the end of 1988 and were replaced by LaLonde and drummer Tim "Herb" Alexander. This lineup recorded Primus' debut release Suck on This, followed by four studio albums: Frizzle Fry, featuring "John the Fisherman"; Sailing the Seas of Cheese, featuring "Jerry Was a Race Car Driver" and "Tommy the Cat"; Pork Soda featuring "My Name Is Mud"; and Tales from the Punchbowl, featuring their most commercially successful single, "Wynona's Big Brown Beaver". In 1996, Alexander left Primus and was replaced by Bryan "Brain" Mantia. This version of the band recorded the original theme song for "South Park" and went on to release two more albums, Brown Album and Antipop, before declaring a hiatus in 2000.

In 2003, Claypool and LaLonde reunited with Alexander and released a DVD/EP, Animals Should Not Try to Act Like People, before touring sporadically through 2009. In 2010, it was announced that Lane had rejoined Primus, replacing Alexander, and the band later digitally released the free June 2010 Rehearsal EP. An eighth album, titled Green Naugahyde, is due for release on on September 12, 2011 in Europe, and September 13 in the United States.

Primus are characterized by their irreverent and often non-serious approach to music. They have released some of their records on Claypool's Prawn Song Records label, the title of which is a parody of Led Zeppelin's Swan Song label.