Leslie Edward Claypool (born September 29, 1963) is an American rock musician, best known as the founder, lead singer, bassist, and primary songwriter of the band Primus since its formation in 1984. Frequently considered to be one of the greatest bassists of all time, his playing style mixes tapping, flamenco-like strumming, whammy bar bends, and slapping.

Outside of Primus, Claypool has also been involved in a number of side projects, including supergroups such as Oysterhead (with Trey Anastasio and Stewart Copeland) and Colonel Claypool's Bucket of Bernie Brains (with Buckethead, Bryan Mantia, and Bernie Worrell). He also fronts the experimental rock projects Colonel Les Claypool's Fearless Flying Frog Brigade and Les Claypool's Fancy Band. He has self-produced and engineered several solo releases from his own studio, Rancho Relaxo, in California. In 2006, he wrote and directed the mockumentary Electric Apricot and released his debut novel South of the Pumphouse. More recently, he has formed musical duos like Duo de Twang (with Bryan Kehoe) and The Claypool Lennon Delirium (with Sean Lennon). He has also appeared in the tv show South Park in the intro and theme song.