"Calm Down" is a song by Nigerian singer Rema, from his debut studio album Rave & Roses (2022). It was released on 11 February 2022 through Jonzing World and Mavin as the album's second single. The song charted across Europe, reaching number one on the Belgian Ultratop 50, Dutch Top 40 and Dutch Single Top 100. In the United Kingdom, "Calm Down" peaked at number three on the UK Singles Chart and spent 27 non-consecutive weeks in the top ten of the chart.

A remix of "Calm Down" with American singer Selena Gomez was released on 25 August 2022. The new version reached number one on both the Billboard US Afrobeats Songs and the Billboard Global Excl. US charts, and peaked at number three on the Global 200 chart. It peaked at number three on the US Billboard Hot 100, marking Rema's first top-ten hit and Gomez's ninth. It also led the U.S. Afrobeats Songs for a record-setting 58 weeks. In the US, it topped the all-genre Radio Songs chart for ten weeks, becoming both artists' first number-one song on the chart. It reached number one on the Canadian Hot 100 chart dated 13 May 2023. According to the International Federation of the Phonographic Industry (IFPI), the remix was the second best-selling global single of 2023, earning 1.89 billion subscription streams equivalents globally. The song is widely regarded as the biggest and most successful Afrobeats song of all time.^{[2][3][4][5][6]}

On 17 August 2022, Selena Gomez posted a photo of herself and Rema on her social media, captioning it "come soon".^[7] The remix was released a week later.^{[citation needed]}

"Calm Down" is all about the events that led me to making love all the time. It started at a party where I saw a girl who stood out from other girls so I felt like shooting my load. We spoke and danced... but her friends didn't let me get any closer which killed the vibe, but afterwards when they weren’t there, we stayed in touch and hit it.

— Rema on how the song came about, Pitchfork^[8]

Miami-based Amanda Ibanez, who also goes by her stage name Kiddo AI, was asked by Interscope senior director of A&R Vanessa Angiuli to write a spec verse for Selena Gomez on the song. Ibanez quickly wrote and recorded two different possible options for a Selena verse. Within a few hours of sending them to Angiuli, Ibanez received a response back from Angiuli who told her that Gomez loved the verse. Within the next few weeks, Ibanez and Gomez began to trade ideas back and forth and refine the verse. Ibanez eventually flew to Los Angeles to complete the song after a request to have more of Gomez on the song.^[9]

Like most girls my age, I grew up watching Selena on Wizards of Waverly Place and always admired her demeanor of being so classy and collected. So the first line is, 'I know I look shy, but for you I get down,' and I thought that that would be kind of fun for her to say, because she’s so proper, I feel, from the outside. I just wanted her to feel herself a little bit.

— Amanda Ibanez on channeling Gomez to write her verse, ^[9]

The song was described as a "vibey"^[10] "feelgood smash hit".^[11] Reviewing the remix, Vanguard writer Adegboyega Remmy Adeleye thought Gomez' "melodic tune complements Rema's vibe perfectly, maintaining the same energy as the original release".^[12]

The song is recorded in the key of B major with a tempo of 107 beats per minute in common time. It follows a chord progression of E–B, and the vocals span from D♯₄ to F♯₅.^[13]

Naming the song one of the best of 2022, Rolling Stone said "Rema likes to call his spin on the Afrobeats sound “Afro-rave,” and it is sublimely lovely all the same. He is the kind of singer who savors simple pop pleasures; with a track that’s appropriately warm, bright, and captivating. The big-eyed wonder in his voice makes it sound like he’s the first guy ever to behold the majesty of girls or colors.^[14] Billboard said the song is organic, and it's slow burn is further underscoring Afrobeats’ increasing mainstream popularity, while naming it the 10th best song of 2023.^[15]