Written by Goulding, Max Martin, Savan Kotecha and Ilya Salmanzadeh, "On My Mind" is an electropop and R&B song whose instrumentation consists of scratchy guitars, trap drums, slapped beats and sharp, syncopated electronica.

Its Western-themed music video, directed by Emil Nava, was inspired by the 1991 film Thelma & Louise and shows Goulding in a revenge story in Las Vegas.

[10] It is an electropop[11] and R&B song,[12][13][14] with its instrumentation consisting in scratchy guitar, slapped beats,[13] trap drums[15] and sharp, syncopated electronica, which according to Idolator's Bianca Gracie, "gladly strays away from the rush of breezy synths that is currently ruling the genre.

"[16] Matthew Norton of NME described it as "hyperactive, insistent R&B with a bit of Rihanna in the 'eh's",[13] while Steven J. Horowitz of Billboard and Maeve McDermott of USA Today both perceived that its "wangy guitars" resemble the Police's "Message in a Bottle".

I think for the past couple of years I've maybe been filtering out lyrics quite a bit and going for a more typical kind of pop structure, but this song, we had so much fun writing it, it just comes back to that basic thing of having that person just constantly stuck in our heads."

"[15] Maeve McDermott of USA Today agreed, calling it "equally ubiquitous as Martin's latest smashes", also naming it "a radio-ready anthem".

[17] Matthew Horton of NME perceived that "[t]here's something of Sheeran in the delivery too", noting that "Goulding sounds like she's toasting as she gets her point across as economically as possible, quickfire lines filling dense, juddery verses" and naming it a "promising switch, whatever the intrigue.

"[24] Brennan Carley of Spin went on to name it "one of her best singles to date",[25] meanwhile Christina Garibaldi of MTV News called it "an up-tempo track that checks all the boxes of what makes a pop smash.

"[22] Nolan Feeney of Time wrote that the song "works its way between your synapses with a twitchy guitar riff and Goulding's lightning-quick verses about a relationship's squandered potential.

"[27] While noting that "[i]t's a fun enough song" and picking as one of the essential tracks on the album, Katherine Flynn of Consequence of Sound wrote that "it doesn't invite multiple listens.

"[28] Kyle Anderson of Entertainment Weekly called it " lively, flashy, confident earworm",[29] while Hazel Cills of Pitchfork praised its "little well-done sass.

"[30] Jon Dolan wrote for Rolling Stone that "Goulding's big voice is compacted into a series of taut flares over clipped hi-hats and Police-like guitar smears",[31] with musicOMH's Rob Mesure agreeing, calling it a "distant cousin of The Police's 'Message in a Bottle' reconfigured with deep bass drops.

"[32] Matt Collar of AllMusic echoed the same thought, naming it "the Police-meets-Rihanna single [that] seem at first like an odd fit for Goulding's highly resonant, throaty chirp of a voice.

[44][45][46] On 25 August 2015, Goulding talked to Capital FM about the concept of the music video, claiming: "Well it involves me and another girl who's really hot and we're sort of like Thelma & Louise", she explained.

Several shots of Goulding and her accomplice in a hair salon, her former lover living his wealthy lifestyle and flirting with another woman are shown while they continue to ride down the main strip.

They ride into the room and stay in place, while her former lover argues his case and pleads with them, while various nude glamour shots of Goulding and scenes before the end of their relationship play in between.

Various scenes of the aftermath are then shown, including the two women back in the salon clinking their glasses, on a rooftop making it rain with money and her accomplice blowing a hole in the casino ceiling with the sawn-off shotgun.

Goulding is then seen walking down a hotel hallway and back in the empty blue room singing, and the video ends with the two women riding off on their horses throwing money in the air.