"Lost Cause" is a song by American singer-songwriter Billie Eilish and the fourth single from her second studio album, Happier Than Ever (2021).

"[10][11] Singer and producer Finneas O'Connell, Eilish's brother and close collaborator on music, confirmed the upcoming release via his Twitter account.

"[12][13] The next day, she announced on her social media accounts that "Lost Cause" and its music video would be released tomorrow, June 2, making it the fourth single from Happier Than Ever.

[18] Taking elements from trip-hop,[19] funk,[20] and 1950s jazz music,[18] it features a crooning vocal style and minimalist instrumentation that consists of drums, a bassline, synthesizers, and acoustic guitar.

[24] To this end, she sought to recreate the musical styles of jazz artists like Frank Sinatra, Julie London, and Peggy Lee on much of the album tracks, including "Lost Cause".

Callie Ahlgrim of Insider interpreted the difference in wording as demonstrative of Eilish's insecurities in spite of her celebratory facade: "[the lines expose] the imbalance of love and affection that continues to haunt her.

[38] P. Claire Dodson of Teen Vogue compared the track to Eilish's previous single "Your Power" (2021), describing the latter as "more vulnerable [and] airy" while saying the former is a "lighter, more playful type of roast".

[41] Stephanie Eckardt of W mentioned that "Lost Cause" is just the "latest indication of where [Eilish]'s headed next leading up to the release of her long-awaited sophomore album Happier Than Ever".

Club opined Eilish is known for "clinging to the melancholy, whispering sad tales of monsters under the bed" but explained the song sees her "looking happier than she's ever been".

[32] Joe Smith of Gigwise stated that "Lost Cause" is a "groovy and subdued effort from Eilish that captures exactly what made her so popular in the first place".

[45] Derrick Rossignol from Uproxx stated Eilish's chest "was exposed than she apparently wanted the world to see, so she covered it with an emoji and wrote in text superimposed onto the video, 'titties was [sic] falling out'".

[46] In the music video, Eilish invites a group of women for a day party in a Los Angeles mansion[47][21][44] to do some interpretive dance moves around a king sized bed,[48][44] move in and out of walk-in closets,[48] twerk,[44] play Twister,[49][50] spray silly string,[36] shoot water guns,[21] drink orange soda,[32] and eat potato chips.

[51] Jordan Darville of The Fader and Brit Dawson of Dazed compared the visual to R&B singer Beyoncé's 2014 single "7/11"'s music video.

[57][58][59] The queerbaiting allegations escalated on June 10, when Eilish posted behind-the-scenes photos of the music video shoot on Instagram with the caption "i love girls.

[67] Darkroom and Interscope Records released "Lost Cause" as Happier Than Ever's fourth single on June 2, 2021, through digital download and streaming media formats.

[70][71] The song dropped off the chart a few weeks after; it re-entered at number 84 upon Happier Than Ever's release,[72] one of nine concurrent entries from Eilish on the Billboard Hot 100.

[81] The song reached the top 25 of national charts in Lithuania (12),[82] New Zealand (15),[83] Canada (16),[84] Switzerland (17),[85] Singapore (18),[86] Portugal and Slovakia (22),[87][88] Norway (23),[89] Austria (24),[90] and Sweden (25).