"Heart-Shaped Box" is a song by the American grunge band Nirvana, written by vocalist and guitarist Kurt Cobain. It appears as the third track on the band's third and final studio album, In Utero, released by DGC Records in September 1993. It was one of two songs on In Utero remixed by Scott Litt prior to the album's release, due to the band's dissatisfaction with the original mixing by producer Steve Albini. The Litt remix also featured additional vocal harmonies and guitar by Cobain, which were the only elements on the album's 12 main tracks not recorded during the original sessions with Albini in February 1993.

In Michael Azerrad's 1993 Nirvana biography, Cobain explained that "Heart-Shaped Box" was written about children with terminal cancer. However, the song is generally also believed to be about his relationship with his wife, Courtney Love, of the American rock band, Hole.

"Heart-Shaped Box" was released as In Utero's first single on August 30, 1993. Although the single was not released in the United States, to avoid competing with album sales, the song generated considerable American radio airplay, reaching number one on the Billboard Modern Rock Tracks chart. The physical single reached the top 10 in several countries, including Portugal, the United Kingdom, Ireland, Finland, and New Zealand. It also reached to Top 40 in numerous other countries.

"Heart-Shaped Box" was the final song performed at Nirvana's last concert, on March 1, 1994, in Munich, Germany. It was also the final Nirvana song to receive a music video before the suicide of Cobain in April 1994. The video, directed by Anton Corbijn, won two awards, including Best Alternative Video, at the 1994 MTV Video Music Awards.

"Heart-Shaped Box" was written by Cobain in early 1992 at the apartment in the Fairfax district of Los Angeles, California, he shared with his wife, the American musician Courtney Love. In a 1994 Rolling Stone interview with David Fricke, Love recalled hearing Cobain work on the guitar riff for the first time:

The only time I asked him for a riff for one of my songs, he was in the closet. We had this huge closet, and I heard him in there working on 'Heart-Shaped Box.' He did that in five minutes. Knock, knock, knock. 'What?' 'Do you need that riff?' 'Fuck you!' Slam. [Laughs] He was trying to be so sneaky. I could hear that one from downstairs.

Cobain briefly set the song aside, then resumed work on it after he and Love moved to an apartment in Hollywood Hills, Los Angeles. Nirvana's first attempts to work on it were unsuccessful; Cobain said he waited for bassist Krist Novoselic and drummer Dave Grohl "to come up with something but it just turned into noise all the time". Eventually, during one jam session, Cobain said he "came up with the vocal style instantly and it just all flowed out real fast. We finally realized that it was a good song."

"Heart-Shaped Box" was first performed live on January 16, 1993, at the Hollywood Rock Festival in São Paulo, Brazil. It was first recorded in the studio a few days later, at BMG Ariola studios in Rio de Janeiro. Producer Craig Montgomery recalled hearing the song during the band's soundcheck in São Paulo, saying that "even then Kurt knew this was the single ... All the other [new] stuff they had was way more noisy and abrasive than this. Even the other sound guys that were out there on the platform with me were going, 'Yeah, this is a good song.'" The band's guitar tech, Ernie Bailey, also had a positive initial reaction to the song in Brazil, saying that "you could tell this was an important song, in a lot of ways. You knew that it just had a lot of weight to it, even the first time you heard it."