"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 is composed in the key of G minor. 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 also serves as the main theme of the 2007 science fiction film Transformers and also appears on Transformers: The Album (2007). Being certified five 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.
"What I've Done" was featured in the video game Guitar Hero World Tour. In January 2011, it was released in a Linkin Park DLC pack for Rock Band 3. The song is also a B-side to the UK single of "Iridescent". An instrumental version of the song is currently used by Sky UK as background music for their interactive services.