"What I've Done" is a song by American rock band Linkin Park. It was released as the first single from their third studio album, Minutes to Midnight (2007), and is the sixth track. The song was released as a radio single on April 1, 2007, as a digital download on April 2, and as a CD single on April 30. The live version of "What I've Done" from Road to Revolution: Live at Milton Keynes was nominated for Best Hard Rock Performance at the 52nd Grammy Awards, but did not win. It serves as the end credits track of the 2007 science fiction blockbuster film Transformers and also appears on Transformers: The Album (2007). Being certified six times platinum by the RIAA, it is the band's most commercially successful single in terms of pure sales, and reached number 7 on the Billboard Hot 100.

Linkin Park is an American rock band formed in Agoura Hills, California, in 1996. The band's lineup consists of vocalist/rhythm guitarist/keyboardist Mike Shinoda, lead guitarist Brad Delson, bassist Dave Farrell, DJ/turntablist Joe Hahn, and drummer Rob Bourdon, with vocalist Chester Bennington also part of the band until his death in 2017. Categorized as alternative rock, Linkin Park's earlier music spanned a fusion of heavy metal and hip hop, while their later music features more electronica and pop elements.