Songfacts®:

• On "In My Head," Ariana Grande sings about how she fell in love with a perfect version of someone she created in her mind, only to later find out he couldn't live up to her fantasy.
  
  Falling, falling, needed something to believe in, oh
  I thought that you were the one
  But it was all in my head
  
  Grande told fans that the track is about "being in love [with] a version of somebody you've created in your head. Falling for someone that they are not."
• A number of Arianators have concluded that the song's lyrics are about Grande's relationship with comedian Pete Davidson, whom the singer began dating in May 2018 following her breakup with Mac Miller. It quickly evolved into an engagement, but the pair broke up a few weeks after Miller's death.
  
  My imagination's too creative
  They see demon, I see angel, angel, angel
  Without the halo, wingless angel
  
  Grande's friends and family were concerned about the speed of their relationship and were relieved when the two split.
  
  Yeah, look at you, boy, I invented you
  Your Gucci tennis shoes, runnin' from your issues
  
  Their relationship turned Davidson into a tabloid fixture and the magazines published photos of the comedian wearing Gucci tennis shoes while out with Grande.
• Parts of the track could apply to Grande's relationship with Mac Miller. In "Thank U, Next," Grande called him an "angel," and the late rapper certainly had his fair share of personal demons. However, it would be unusually cruel of the singer to write such a song about Miller months after his death.
• The opening lines are spoken by Grande's close friend Doug Middlebrook. He warns the singer that she's "in love with a version of a person" that she's created in her head.
  
  Grande explained Middlebrook's appearance on Twitter: "He was a major help to me through some very difficult moments so I wanted to capture that a little."
• Grande wanted to use a Jack Nicholson quote from the 1980 movie The Shining where he said, "You seem to have things strangely confused in your mind." However, the singer's people couldn't clear it, so she plumped for Middlebrook's mini speech instead.
• This was co-wriiten and co-produced by Andrew "Pop" Wansel, who is one of Nicki Minaj's key writing partners. He also contributed towards the Thank U Next tracks "Imagine" and "Fake Smile."
• The minimalist video sees a dismembered Grande floating around a fluorescent box. The clip was directed by Bardia Zeinali, whose credits include Shawn Mendes' "If I Can't Have You" and Carly Rae Jepsen's "Party For One."
  
  "It's a little bit sci-fi, it's a little bit [Stanley] Kubrick, it's a little Y2K," said Zeinali to Vogue about the video's concept. "It kind of started out by just finding what makes Ariana iconic: it's the voice, it's the ponytail, it's the boots, it's the silhouette. So we decided we wanted to create an iconic video where we're isolating the Ariana iconography and playing it up and having a good time with it."