Ian Matthias Bavitz (born June 5, 1976), better known by his stage name Aesop Rock, is an American hip hop recording artist and producer residing in Portland, Oregon. He was at the forefront of the new wave of underground and alternative hip hop acts that emerged during the late 1990s and early 2000s. He was signed to El-P's Definitive Jux label until it went on hiatus in 2010. In a 2010 retrospective, betterPropaganda ranked him at number 19 at the Top 100 Artists of the Decade.

He released his first album Music for Earthworms in 1997, with Float following 3 years later. Labor Days, his third studio album, was released September 18, 2001. His next release came two years later, titled Bazooka Tooth, released September 23, 2003. His fourth studio album, None Shall Pass, was released August 28, 2007. Its titular song became one of Ian's most popular and well-known songs. His seventh record, Skelethon, was released July 10, 2012. His seventh release, The Impossible Kid, came out on April 29, 2016. His eighth and most recent album, Spirit World Field Guide, came out on November 13, 2020.

He is a member of the groups The Weathermen, Hail Mary Mallon (with Rob Sonic & DJ Big Wiz), The Uncluded (with Kimya Dawson) and Malibu Ken (with Tobacco).

Regarding his name, he said: "I acquired the name Aesop from a movie I had acted in with some friends. It was my character's name and it sort of stuck. The rock part came later just from throwing it in rhymes."