John Anthony Frusciante (/fruːˈʃɑːntɛ/; born March 5, 1970) is an American guitarist, singer, songwriter, and producer. He is best known as the former guitarist of the rock band Red Hot Chili Peppers, with whom he recorded five studio albums, and of whom he was a member from 1988 until 1992 and again from 1998 until 2009. He has recorded with numerous other artists, including The Mars Volta, for whom he was a studio guitarist (and occasional live performer) from 2002 until 2008; Josh Klinghoffer and Joe Lally, with whom he released two albums as Ataxia; and various collaborations with both Klinghoffer and Omar Rodríguez-López. Frusciante also has an active solo career, having released eleven solo albums and five EPs; his recordings include elements ranging from experimental rock and ambient music to new wave and electronica.

Frusciante joined the Red Hot Chili Peppers at the age of eighteen, first appearing on the band's 1989 album, Mother's Milk. The group's follow-up album, Blood Sugar Sex Magik (1991), was a breakthrough success. Frusciante became overwhelmed by the band's new popularity and quit in 1992. He became a recluse and entered a long period of drug addiction, during which he released his first solo recordings: Niandra Lades and Usually Just a T-Shirt (1994) and Smile from the Streets You Hold (1997). In 1998, he successfully completed drug rehabilitation and rejoined the Red Hot Chili Peppers. Their next album, Californication (1999) would eventually go on to sell 16 million copies. His album To Record Only Water for Ten Days was made in 2001. A fourth album with the Chili Peppers, By the Way was released in 2002. On a creative spree, Frusciante released six solo albums in 2004; each album explored different recording techniques and genres. 2006 saw the release of his fifth and final album with the Chili Peppers, Stadium Arcadium. In 2009, Frusciante released The Empyrean, which features Flea and Josh Klinghoffer, and announced he had again parted ways with the Chili Peppers. Frusciante has produced and/or recorded with the Wu-Tang Clan, The Mars Volta and Omar Rodriguez Lopez, Swahili Blonde, Black Knights, The Bicycle Thief, Glenn Hughes, Ziggy Marley, Johnny Cash, George Clinton, and others.