"Bad Guy" (stylized in lowercase) is a song by the American singer-songwriter Billie Eilish and the fifth single from her first studio album, When We All Fall Asleep, Where Do We Go?

Dave Meyers directed the music video, which depicts Eilish involved in several activities such as wild dancing, suffering a nosebleed and sitting on the back of a man doing push-ups.

[14] In an interview with Rolling Stone, the use of a Sydney pedestrian traffic light sound in the song was revealed; it originates from a phone recording made by Eilish in February 2017.

[18][19] In the lyrics, Eilish taunts a lover for being a bad guy; as the song progresses she suggests she is tougher than him, singing in a "nonchalant, self-effacing murmur".

[17] Analyzing the lyrics of "Bad Guy", Caitlin White of Uproxx wrote that they see "a woman's teenage voice boast of its power, assert her sexual dominance, and use men as playthings instead of sing about being used as one by them".

She continued; "'Bad Guy' positions a young female pop star in a role that's usually reserved for men working in rock or hip hop".

[2] Labeling "Bad Guy" as a "low-key banger", Stereogum's Chris DeVille drew comparisons between the song and the work of Lorde and Fiona Apple.

[21] Writing for PopBuzz, Sam Prance said "Bad Guy" is "iconic" and dubbed the "duh" lyric as "already one of the standout musical moments of 2019".

[22] In a negative review, Pitchfork's Stacey Anderson criticized Eilish for "bragging about statutory rape" and said she found the song "stale".

[25] Upon the release of When We All Fall Asleep, Where Do We Go?, "Bad Guy" debuted at number seven on the US Billboard Hot 100 on the week ending April 13, 2019, as Eilish's first top ten entry on the chart.

"Bad Guy" ended the record-breaking 19-week run of "Old Town Road" by Lil Nas X featuring Billy Ray Cyrus.

[47] Internationally, "Bad Guy" reached number one in Australia,[48] Canada,[49] Estonia,[50] Finland,[51] Greece,[52] Hungary,[53] Iceland,[54] Latvia,[55] Lithuania,[56] New Zealand,[57] Norway,[58] and Russia.

[60][61] becoming the first song from an female artist born this century to go Diamond in the US[62] "Bad Guy" was the best-performing global single of 2019 with combined sales and track-equivalent streams of 19.5 million units according to the International Federation of the Phonographic Industry (IFPI).

[64] A music video for "Bad Guy" was directed by Dave Meyers and was uploaded to Eilish's official YouTube channel on March 29, 2019.

[2][66] She eventually kicks her way through a wall while wearing a yellow sweatshirt and sweatpants, and hands her dental brace to a man, Eric Lutz,[68] on her right.

[10][69][70][71] One comment to the clip on YouTube posted by Seth Everman, reading "I'm the bald guy", became the most-liked on the platform, gathering over three million likes[72] and also surpassed one billion views in November 2020, which made Google celebrate the milestone created an 'Infinite Bad Guy' interactive site that allowed users to switch between over 15,000 different covers of the song available on YouTube.

[74] Chloe Gilke, writing for Uproxx, said the video takes several of the song's lyrics literally and that it is "awash in primary colors and black and white, Eilish's bold aesthetic".

[84] On September 29, 2019, Eilish performed the song on Saturday Night Live; her routine was compared to Lionel Richie's "Dancing on the Ceiling" (1986) music video.

[92] In April 2019, Team Blake Shelton's Kendra Checketts covered "Bad Guy" on the Live Playoff round of the sixteenth season of The Voice.

[93] In May 2020, Anthrax drummer Charlie Benante and Suicidal Tendencies bassist Ra Diaz covered the song virtually during the COVID-19 lockdowns.

[95] "Bad Guy" was used for an advertisement for clothing manufacturer Calvin Klein's "My Truth" campaign,[96] as well as commercials for Kia Seltos.

[106] A piano cover of "Bad Guy" by composer Ramin Djawadi was featured in the third episode of the fourth season of Westworld.

[115] The remix has identical credits to the original "Bad Guy" with the addition of Bieber and Jason Boyd as songwriters and composers.

[114] Billboard's Andrew Unterberger wrote; "Bieber's clearly having fun with his guest verse and ad-libs – the remix's high point might come with his mid-verse "skrrt!"

[117] Stereogum editor Chris DeVille considered Bieber's vocals "entirely out of place," concluding that "he basically ruins a great song.