"Lights" was originally announced as a single on 8 September 2010 on Goulding's official Twitter page, with a release date scheduled for 1 November 2010.

[5] A digital EP was released in the United Kingdom on 13 March 2011, containing Goulding's acoustic cover version of Rihanna's "Only Girl (In the World)" as performed on BBC Radio 1's Live Lounge on 10 December 2010.

[6][7] The single version of "Lights" also appears as a bonus track on the international edition of Goulding's second studio album, Halcyon.

Horatia Harrod of The Daily Telegraph commented that the song is "threaded with dark thoughts, but set to an airy pop production bordering on polite.

She has the magical ability, not unlike her heroine, Björk, to sing with a sort of controlled tremulousness: her voice aches with vulnerability but never breaks.

"[18] On 8 October 2014, "Lights" was honoured as Song of the Year at American Society of Composers, Authors and Publishers' (ASCAP) 34th annual awards in London.

[25] When "Lights" reached number 40 in its 19th week, on the issue dated 12 May, the song attained the third-slowest climb to the top 40 by a female artist, after Norah Jones's "Don't Know Why" and KT Tunstall's "Suddenly I See".

[26] In its 29th week, the song made Hot 100 history by achieving the longest climb to the chart's top five not aided by country-to-pop crossover success or multiple releases.

[30] "Lights" ascended to number one on the Radio Songs chart on the issue dated 25 August 2012, making Goulding the first female solo artist to send a debut Radio Songs entry to number one since Adele led the list in 2011 and 2012 with her singles "Rolling in the Deep", "Someone Like You" and "Set Fire to the Rain".

[33] In late December 2012, "Lights" spent its 52nd week on the Hot 100 at number 43, becoming the 30th song in the chart's history to spend a year on the tally.

[43] The video shows Goulding dancing, playing the drums and the tambourine whilst different lighting effects including lasers surround her as she sings.

[46] She also performed "Lights" on BBC Radio 1's Live Lounge on 12 March 2011, along with a cover of José González's version of The Knife's "Heartbeats".

[53] American rapper Lupe Fiasco sampled the Bassnectar remix of "Lights" for his song "Lightwork", from his 2011 mixtape Friend of the People: I Fight Evil.

[55] At the Drive-In and The Mars Volta guitarist Omar Rodríguez-López covered the song on his 2016 solo album Blind Worms Pious Swine.

[56] American hard rock band Through Fire recorded a cover of "Lights" on their debut studio album, Breathe (2016).