Florence and the Machine (stylised as Florence + the Machine) are an English indie rock band formed in London in 2007 by lead vocalist Florence Welch, keyboardist Isabella Summers, guitarist Rob Ackroyd, drummer Christopher Lloyd Hayden and harpist Tom Monger. The band's music features dramatic, eccentric production and Welch's powerful vocals. Their sound has been described as a combination of various genres, including rock and soul.

The band's debut studio album, Lungs, was released on 3 July 2009, and held the number-two position for its first five weeks on the UK Albums Chart. On 17 January 2010, the album reached the top position, after being on the chart for twenty-eight consecutive weeks. As of October 2010, the album had been in the top forty in the United Kingdom for sixty-five consecutive weeks, making it one of the best-selling albums of 2009 and 2010. The group's second studio album, Ceremonials, released in October 2011, entered the charts at number one in the UK and number six in the US. The band's third studio album, How Big, How Blue, How Beautiful, was released on 2 June 2015. It topped the UK charts, and debuted at number one on the US Billboard 200, their first to do so. The album reached number one in a total of eight countries and the top ten of twenty. Also in 2015, the band was the headlining act at Glastonbury Festival, making Welch the first British female headliner of the 21st century.

The BBC played a part in their rise to prominence by promoting Florence and the Machine as part of BBC Music Introducing. At the 2009 Brit Awards, they received the Critics' Choice Award. Lungs won the Brit Award for Best British Album in 2010, while Florence and the Machine have been nominated for six Grammy Awards including Best New Artist and Best Pop Vocal Album.

The name of Florence and the Machine is attributed to Florence Welch's teenage collaboration with Isabella "Machine" Summers. Welch and Summers performed together for a time under the name Florence Robot/Isa Machine. According to Welch, "The name Florence and the Machine started off as a private joke that got out of hand. I made music with my friend, who we called Isabella Machine to which I was Florence Robot. When I was about an hour away from my first gig, I still didn't have a name, so I thought 'Okay, I'll be Florence Robot Is A Machine', before realising that name was so long it'd drive me mad." In addition to Summers (keyboards), the current band members include musicians Robert Ackroyd (guitar), Chris Hayden (drums, percussion and backing vocals), Mark Saunders (bass guitar and percussion) and Tom Monger (harp). In the past, Welch has praised her band for understanding her creative process, claiming, "I've worked with most of them for a long time and they know my style, know the way I write, they know what I want."

In 2007, Welch recorded with a band named Ashok, who released an album titled Plans on the Filthy Lucre/About Records label. This album included the earliest version of her later hit "Kiss with a Fist", which at this point was titled "Happy Slap".

Florence and the Machine released their first album Lungs in the Netherlands and Ireland on 3 July 2009. The album was produced by James Ford, Paul Epworth, Steve Mackey, Isabella Summers and Charlie Hugall. The album was officially launched with a set at the Rivoli Ballroom in Brockley, south-east London. It peaked at number one in the UK and number two in Ireland. As of 6 August 2009, the album had sold more than 100,000 copies in the UK and by 10 August it had been at number two for five consecutive weeks. Following its 25 July 2009 release for download in the United States, the album entered the charts at number seventeen on the Billboard Heatseekers Albums chart, ultimately peaking at number one. The album was released physically in the US on 20 October by Universal Republic.

"Kiss with a Fist" was released as the album's lead single on 9 June 2008. The track was featured on the soundtrack to the films Wild Child (2008), Jennifer's Body (2009), and St Trinian's 2: The Legend of Fritton's Gold (2009), as well as in the television series 90210, Community and Saving Grace. Follow-up single "Dog Days Are Over", released on 1 December 2008, was recorded with no instruments in a studio the "size of a loo". The song was used in the American television series Gossip Girl, Covert Affairs, in the British television series Skins, and in the theatrical trailer for the 2010 comedy-drama film Eat Pray Love, starring Julia Roberts. "Dog Days Are Over" was also featured in the Glee episode "Special Education", where it was covered by Jenna Ushkowitz and Amber Riley. "Rabbit Heart (Raise It Up)" was released on 22 June 2009 as the third single from the album.

After the release of Lungs, "Drumming Song" and a cover of the Source and Candi Staton's 1986 song "You've Got the Love" were released as singles. "Cosmic Love" was released on 5 July 2010 as the sixth and final single from Lungs, with a music video having already been shot. The song was featured in several American television shows, including Grey's Anatomy, The Vampire Diaries, V, Nikita and So You Think You Can Dance. The band also made a guest appearance on 7 February 2011 episode of Gossip Girl, titled "Panic Roommate", where they performed an acoustic rendition of "Cosmic Love". On 12 May 2010, it was announced that Florence and the Machine would provide a track called "Heavy in Your Arms" for the soundtrack to The Twilight Saga: Eclipse, the third film of The Twilight Saga. Eclipse was released in cinemas on 30 June 2010, with "Heavy in Your Arms" playing during the end credits. The music video followed on 7 July 2010. An exclusive remix of "I'm Not Calling You a Liar" is featured in the 2011 video game Dragon Age II as "I'm Not Calling You a Liar (Dragon Age II: Varric's Theme)", produced by the game's composer Inon Zur.