A mid-tempo love song, Carolyn Menyes from Music Times described "Lonely Girl" as having "a "Buddy Holly"-like swing to the beat and the blend of heavy guitars mixed with a soft-singing Rivers Cuomo recalls distinctively The Green Album era".[2] Ian Cohen at Pitchfork Media notes that the song "isolates the second verse of "Only in Dreams" and reworks Cuomo's Japanese curio "Homely Girl" into a legitimate buzzy throwback."[3] Dan Reilly from Spin characterizes the song as more straightforward than "The British Are Coming", and more similar to "Back to the Shack".[4] The song also contains "rowdy hooks and fast-paced gallop".[5]
Carolyn Menyes at Music Times states "'Lonely Girl' seems to blend together some of the best moments from Weezer's most beloved albums."[2] Tom Breihan from Stereogum described it as "a fine example of the sort of supercharged power-pop that this band does so well when Rivers Cuomo is feeling motivated".[1]Slant Magazine writer Blue Sullivan notes that the song "finds the band finally casting off its slacker straitjacket".[6] Mattison Keesey of AltWire noted that the song is "without a doubt classic Weezer" and compared it to the albums Weezer (1994) and Pinkerton.[7] Allan Raible from ABC News was more critical of the song, noting the "painfully easy rhyming sections".[8]
