[1][2] The track was written by Jepsen, Tavish Crowe, Julia Karlsson, and Anton Rundberg, and produced by Hightower and Captain Cuts.

[6] Mike Wass of Idolator said that as the lead single for Jepsen's fourth studio album, it is "likely to cement her status as the hipster's guilty pleasure with a collection of cute, clever and slightly offbeat bops".

[3] Despite being promoted as the lead single from Dedicated, "Party for One" is not included in the standard track listing and only appears on select digital and deluxe editions of the album.

[12] Brooke Bajgrowicz of Billboard said the track is "driven by an electric beat" and compared its "infectious pop sound" to "Call Me Maybe" and "I Really Like You".

[13] Writing for Pitchfork, Bobby Finger felt that "In the pantheon of pop breakup anthems, Jepsen's newest single lacks the aching detail of 'Dancing on My Own' or the Max Martin alchemy of 'Since U Been Gone,' but it's a satisfying intimation that E•MO•TION could be getting a sequel soon".