Thomas Smith from NME said the song was "a far cry from her now-relentless and brooding productions, but still irresistibly catchy." Insiders Claudia Willen called it "a creative and brutal portrayal of just how ruthless breakups can be," though stated that "the song doesn't beg to be listened to on loop as some of Eilish's other breakup songs do, like 'Watch' and 'Bitches Broken Hearts'. Spruch commented that "Party Favor" can "be easily overlooked when standing next to early hits 'Bellyache' and 'Ocean Eyes'," but that it "still has a whole lot of that Eilish persona." Commercially, the track has been certified gold in the United States and Canada by the Recording Industry Association of America (RIAA) and Music Canada (MC), respectively.
