"Underneath" is a song recorded for Alanis Morissette's seventh studio album, Flavors of Entanglement, which was produced by Guy Sigsworth. It is the album's first single. The song was digitally released on April 15, 2008 after originally being scheduled for March 25. According to Morrisette, "'Underneath' is about how you can only change the world after you change yourself.
In January 2008, New York magazine named "Underneath" "the best song we've heard all day", and About.com said the video is "well worth watching and is a great reminder of the talents of Alanis", and that the song's lyrics are "classic Alanis". Blender magazine gave the video two stars, writing, "[the song] features a bunch of weak, tentative and already dated beats—Madonna tried this same strategy (and pulled it off with significant aplomb) exactly 10 years ago. So while her voice sounds even a bit harsher when set against the track's popping, mechanical drums, the video just confuses [...] Not a lot of "comeback of the year" potential here."
"Underneath" has been certificated Diamond by ABPD for sold 500,000 digital downloads on Brazil. Morissette is the only female artist of all time to have a diamond certificated song in that country.