Louder Now is the third studio album by American rock band Taking Back Sunday. In April 2005, the group had begun writing material for the album. Two months later, they signed with Warner Bros. Records and contributed a song to the Fantastic Four soundtrack. Soon afterwards, the group rented a room in Manhattan where they composed songs for Louder Now. They came up with 20 songs, discarding half of them and recording demos of the remainder. The group began recording Louder Now with Eric Valentine in September 2005 at Barefoot Studios in Los Angeles, California. After Warner Bros. told them they did not need to rush, they recorded new demos. Recording ended on New Year's Day, 2006, and was followed by a tour of the UK, Australia and the U.S.

Louder Now was released on April 25, 2006, on Warner Bros. Records. Several weeks later, "MakeDamnSure" was released as a single; this was followed by a tour with Angels & Airwaves. A music video was released for "Twenty-Twenty Surgery", and the single was released a month later. A video for "Liar (It Takes One to Know One)" was released in September, before the single's release in November. Taking Back Sunday then began a two-month stint as part of the Taste of Chaos tour. A video album, The Louder Now DVD: PartOne, was released in December. The album included videos of the recording process, tour footage and music videos. "What's It Feel Like to Be a Ghost?" was released as a single on New Year's Eve. In early 2007 the group toured North America, followed by the release of "My Blue Heaven" as a single in April. After a tour with Linkin Park, guitarist Fred Mascherino left the group and was replaced by Matthew Fazzi.

Louder Now received generally favorable reviews from critics, and was voted Kerrang!'s album of the year. It debuted at number two on the Billboard 200, selling 158,000 copies in its first week after release, reached the top 10 of several Billboard charts and the top 20 in Canada, Australia and the UK. Two months after its release, Louder Now was certified gold by the RIAA for sales of 500,000 copies and was later certified silver by the BPI for sales of 60,000 copies. As of May 2009, the album has sold 674,000 copies in the U.S.