Under the Iron Sea is the second studio album by the English rock band Keane, released on 12 June 2006. During its first week on sale in the UK, the album opened at number one, selling 222,297 copies according to figures from the Official Chart Company. In the United States, the album debuted at number four on the Billboard 200, selling 75,000 copies in its first week there. Since its release, the album has sold over three million copies worldwide.

Keane are an English alternative rock band from Battle, East Sussex, formed in 1995. They met while at Tonbridge School together. The band comprises Tom Chaplin, Tim Rice-Oxley, Richard Hughes and Jesse Quin. Their original line-up included founder and guitarist Dominic Scott, who left in 2001.