[2] "When You're Gone" is a pop-rock song that lyrically sees Mendes singing about the end of a relationship, similar to his previous single from late 2021, "It'll Be Okay".

[4] Before the release of "When You're Gone", Billboard's Jason Lipshutz described the song as "a rollicking pop-rock track that sounds ready for radio play" and added that it "possess[es] a weight and polish that could make them staples of Mendes' set for years to come, and hint at promising new paths for his songwriting".

[5] Khushboo Malhotra of CelebMix likewise stated that "[t]he song heralds a new musical era that appears promising and elevated while widening his aural and stylistic horizons", calling it a "heartbreakingly beautiful single".

It starts with a black-and-white resolution and sees Mendes recording the song in a studio and meeting up with fans.

[7] Three days before its release, Mendes teased the video on the video-sharing app TikTok, which saw him dancing shirtless, with the caption: "this is unusual behavior".