Lasse Marhaug (born 10 September 1974) is a Norwegian musician who primarily works in the field of noise music but frequently drifts into other areas such as improvisation, jazz, rock and extreme metal.

He currently participates in the projects Nash Kontroll (with Mats Gustafsson and Dror Feiler), DEL, and Testicle Hazard.

Other collaborative partners include Tore Honoré Bøe, Marc Broude, Anla Courtis, Carlos Giffoni, John Hegre, Kommissar Hjuler und Frau, Merzbow, Paal Nilssen-Love, Nordvargr, Maja Ratkje, The Skull Defekts, Ronnie Sundin, Sunn O))), Ken Vandermark, Jon Wesseltoft, Runhild Gammelsæter, John Wiese, Jenny Hval and Kelly Lee Owens.

In 2013, PAN GU's Primeval Man Born of the Cosmic Egg, Marhaug's collaboration with The Observatory's Leslie Low, made it to SPIN's Top 20 Avant albums of 2013.

He also runs Prisma Records with Lars Mørch Finborud which releases music performed at the Henie-Onstad Art Centre.