"Teeth" is a song by Australian pop rock band 5 Seconds of Summer, released on 21 August 2019 as the second single from the band's fourth studio album Calm. It also appears on the third season soundtrack of the Netflix series 13 Reasons Why. Written by band members Luke Hemmings and Ashton Irwin with Ali Tamposi, and produced by Andrew Watt and Louis Bell, the track features guitar from Tom Morello of Rage Against the Machine, and its music video was released the same day. The track's instrumental samples "So What", an unreleased song by late American rapper Juice Wrld and also produced by Bell and Watt, which was recorded in 2018 during the sessions for Wrld on Drugs, Juice Wrld's collaborative mixtape with American rapper Future.
Similarly to the band's previous single "Easier", an alternate "Live from the Vault" version of the song was released. "Teeth – Live from the Vault" was released on 29 October 2019 and was accompanied by a video directed by Thibaut Duverneix. At the APRA Music Awards of 2020, "Teeth" was nominated for Song of the Year, while it won Song of the Year at the 2020 ARIA Music Awards.