"Burn" is a song by American R&B singer Usher, which he wrote with Jermaine Dupri and Bryan-Michael Cox. The song was produced by Dupri and Cox for Usher's fourth studio album, Confessions (2004). A downtempo track about the breakup of a relationship, it was originally planned as the album's lead single, but "Burn" was pushed back after favorable responses for the song "Yeah!". "Burn" was eventually released as the second single from the album on March 21, 2004. "Burn" is considered to be one of Usher's signature hits.

"Burn" topped various charts around the world, including the US Billboard Hot 100 for eight non-consecutive weeks; it succeeded "Yeah!" at number one. Both singles gave Usher nineteen consecutive weeks at the top spot, longer than any solo artist of the Hot 100 era. "Burn" was certified platinum in Australia and United States and gold in New Zealand. The song was well received by critics and garnered award nominations. In 2009, it was named the 21st most successful song of the 2000s on the Billboard Hot 100 Songs of the Decade. This song won the 2005 Kids' Choice Award for Favorite Song.

When Usher planned to make a new record after his third album, 8701 (2001), he decided to not branch out much with collaborators and continue building music with his previous producers. Usher again enlisted record producer Jermaine Dupri, who had collaborated on his two previous albums, along with The Neptunes and R. Kelly, among others, to work on his fourth studio album, Confessions (2004). Dupri contacted his frequent collaborator Bryan-Michael Cox, who had also made hits like the 2001 single "U Got It Bad" for Usher. During an early session for the album, Dupri and Cox talked about a situation which later became "Burn". At that time, Usher's two-year relationship with TLC's Chilli was flaming out. They said, "Yo, you gotta let that burn ... That's a song right there", and started writing.

Usher submitted the album to his label Arista Records after he felt it was completed. After he and the company's then-president Antonio "LA" Reid listened to the songs, they felt the album needed a first single and that they needed to create one or two more songs, which caused the album's release to be postponed. Usher went back to the studio and collaborated with Lil Jon, who said, "He needed a single. They had 'Burn,' 'Burn' was hot, but they needed that first powerful monster. That's when I came in." They worked on few more tracks, including "Red Light", which was not included in the first release of the album, and "Yeah!", which features Ludacris and Lil Jon.

Label personnel were undecided as to what to consider as the lead single. Reid was considering whether "Yeah!" would be released then, being as they also had "Burn". Usher was doubtful if the former was the right choice, after he wanted an R&B record. Until "Yeah!" was leaked, "Burn" was chosen as the official first single from Confessions. "Yeah!", which was intended as a promotional song and a teaser for Usher's fans, was released to street DJs and mixtapes. However, the favorable response to the song led to a change; "Yeah!" was the lead single and "Burn" was set as its follow-up. "Burn" was sent to US rhythmic contemporary and urban contemporary radio stations on March 1, 2004. It was released commercially in the United States on March 21, 2004, as a CD single, digital download, and 7-inch single. In the United Kingdom, a CD and 12-inch single were issued on June 28, 2004.

Usher decided about the new material "to let it all hang out by singing about some of his own little secrets, as well as a few bones from his homies' skeleton-filled closets." The public speculated that he was referring to his recent personal struggles, on which he promised a "real talk".

In early 2004, Usher broke up with Chilli due to "irreconcilable differences and because they found it almost impossible to make compromises." Usher said in an interview: "It's unfortunate when you have to let a situation go because it's not working", which added reference to the breakup. It was later revealed that Chilli in fact broke up with Usher because of cheating, and the media said otherwise because of the lyrics in the song, which was not based on their relationship. Dupri, however, confessed that his personal life is the real story of the album. Usher said he took inspiration collectively by looking at his friends' personal situations.

"Burn" is a slow jam R&B ballad. The song is performed with a moderate groove. It is composed in the key of D-flat major. The melody line of the song has influences from "Ignition (Remix)" by R. Kelly. "Burn" has a combination of robotic noises, synthesized strings and guitar lines.