Kim Anand Thayil (born September 4, 1960) is an American musician best known as the lead guitarist of the Seattle-based rock band Soundgarden, which he co-founded with singer Chris Cornell and bassist Hiro Yamamoto in 1984. Cornell and Thayil remained as the original members of the band until Cornell's death in 2017, and the band's subsequent split in 2018. Thayil was named the 100th greatest guitarist of all time by Rolling Stone in 2010, and the 67th greatest guitarist of all time by SPIN in 2012. Thayil has won two Grammy Awards as a member of Soundgarden.

Born in Seattle, Washington in 1960, Thayil grew up in the Chicago suburb of Park Forest. His Malayali parents came from the state of Kerala in India to Seattle. His mother was a music teacher who studied to be a concert pianist at the Royal Academy of Music. His father earned a degree in chemical engineering, received employment in Chicago and moved there with his family.

Thayil started writing lyrics at 12 years old. In 1977, he formed his first band in Chicago, Bozo and the Pinheads, a punk rock band. They did both original songs (written by Thayil and inspired by his punk music tastes) and cover tunes (mostly Sex Pistols, Devo, and Ramones). Their first gig was at a school talent show for an audience of about 500 people.

He played guitar in a post-punk band called Identity Crisis in 1980 and released a 7-inch EP called Pretty Feet.

Thayil met Hiro Yamamoto at Rich East High School in Park Forest. He graduated, along with Hiro Yamamoto, from the Active Learning Process School (ALPS) at Rich East High School in 1979, the same school Bruce Pavitt graduated from two years earlier, in 1977. He and Yamamoto decided to move to Olympia, Washington, to study at The Evergreen State College, but they were unable to find jobs and decided to move to Seattle. There, Thayil earned money as a DJ for KCMU and earned a degree in philosophy at the University of Washington. In Seattle they also met Chris Cornell, a roommate, and the three formed Soundgarden in 1984.

Soundgarden became the first of Seattle's grunge bands to sign with a major label (A&M Records). They went on to release five albums, including three which went platinum at least once, and won two Grammys.

Thayil became acclaimed for his guitar work, which was typically characterized by heavy riffing, and was cited among other grunge guitarists as an influence and a pioneer of the "Seattle Sound." In 1994, Thayil commented, "I think Soundgarden is a pretty good band and I'm a fine guitarist. I'm not God, but I'm certainly not average. I feel very comfortable with the fact that not many other people can do what I do on guitar. I think my guitar is happy with the way I play it."

Originally one of Soundgarden's main songwriters, Thayil's contributions as a writer eventually dwindled to just one song on Down on the Upside, "Never the Machine Forever", although he contributed to details in every song, as did every band member. Thayil explained that "Collaboration was paramount in our early music, especially right at the beginning when it was me on guitar, Hiro on bass and Chris on drums", but eventually all four members became songwriters of their own, "all writing guitar parts that I had to learn." This led him to do "Never the Machine Forever" all on his own, as Thayil thought "Well, if I'm going to have a song on this fucking record, I'm going to have to write lyrics."